Comparison of American and British English

The English language was first introduced to the Americas by British colonisation, beginning in the late 16th and early 17th centuries. The language also spread to numerous other parts of the world as a result of British trade and colonisation and the spread of the former British Empire, which, by 1921, included 470–570 million people, about a quarter of the world's population. Written forms of British and American English as found in newspapers and textbooks vary little in their essential features, with only occasional noticeable differences.
Over the past 400 years, the forms of the language used in the Americas—especially in the United States—and that used in the United Kingdom have diverged in a few minor ways, leading to the versions now often referred to as American English and British English. Differences between the two include pronunciation, grammar, vocabulary (lexis), spelling, punctuation, idioms, and formatting of dates and numbers. However, the differences in written and most spoken grammar structure tend to be much less than in other aspects of the language in terms of mutual intelligibility. A few words have completely different meanings in the two versions or are even unknown or not used in one of the versions. One particular contribution towards formalising these differences came from Noah Webster, who wrote the first American dictionary (published 1828) with the intention of showing that people in the United States spoke a different dialect from those spoken in the UK, much like a regional accent.
This divergence between American English and British English has provided opportunities for humorous comment: e.g. in fiction George Bernard Shaw says that the United States and United Kingdom are "two countries divided by a common language"; and Oscar Wilde says that "We have really everything in common with America nowadays, except, of course, the language" ("The Canterville Ghost", 1888). Henry Sweet incorrectly predicted in 1877 that within a century American English, Australian English and British English would be mutually unintelligible ("A Handbook of Phonetics"). Perhaps increased worldwide communication through radio, television, the Internet and globalisation has tended to reduce regional variation. This can lead to some variations becoming extinct (for instance "the wireless" being progressively superseded by "the radio") or the acceptance of wide variations as "perfectly good English" everywhere.
Although spoken American and British English are generally mutually intelligible, there are occasional differences which might cause embarrassment—for example, in American English a "rubber" is usually interpreted as a "condom" rather than an "eraser"; and a British "fanny" refers to the female pubic area, while the American "fanny" refers to an "ass" (US) or an "arse" (UK).
Vocabulary.
The familiarity of speakers with words and phrases from different regions varies, and the difficulty of discerning an unfamiliar definition also depends on the context and the term. As expressions spread with the globalisation of telecommunication, they are often but not always recognised as foreign to the speaker's dialect, and words from other dialects may carry connotations with regard to register, social status, origin, and intelligence.
Words and phrases with different meanings.
Words such as "bill" and "biscuit" are used regularly in both AmE and BrE but can mean different things in each form. The word "bill" has several meanings, most of which are shared between AmE and BrE. However, in AmE "bill" often refers to a piece of paper money (as in a "dollar bill") which in BrE is more commonly referred to as a note. In AmE it can also refer to the visor of a cap, though this is by no means common. In AmE a biscuit (from the French "twice baked" as in biscotto) is a soft bready product that is known in BrE as a scone or a specifically hard, sweet biscuit. Meanwhile, a BrE biscuit incorporates both dessert biscuits and AmE cookies (from the Dutch 'little cake').
As chronicled by Winston Churchill, the opposite meanings of the verb "to table" created a misunderstanding during a meeting of the Allied forces; in BrE to table an item on an agenda means to "open it up" for discussion whereas in AmE, it means to "remove" it from discussion, or at times, to suspend or delay discussion; e.g. "Let's table that topic for later".
The word "football" in BrE refers to association football, also known as soccer. In AmE, "football" means American football. The standard AmE term "soccer", a contraction of "association (football)", is actually of British origin, derived from the formalisation of different codes of football in the 19th century, and was a fairly unremarkable usage (possibly marked for class) in BrE until relatively recently; it has lately become perceived as an Americanism. In international (i.e. non-American) context, particularly in sports news outside English-speaking North America, American (or US branches of foreign) news agencies also use "football" to mean "soccer", especially in direct quotes.
Similarly, the word "hockey" in BrE refers to field hockey and in AmE, "hockey" means ice hockey.
Words with completely different meanings are relatively few; most of the time there are either (1) words with one or more shared meanings and one or more meanings unique to one variety (for example, bathroom and toilet) or (2) words the meanings of which are actually common to both BrE and AmE but that show differences in frequency, connotation or denotation (for example, "smart", "clever", "mad").
Some differences in usage and meaning can cause confusion or embarrassment. For example, the word "fanny" is a slang word for vulva in BrE but means buttocks in AmE—the AmE phrase "fanny pack" is "bum bag" in BrE. In AmE the word "pissed" means being annoyed whereas in BrE it is a coarse word for being drunk (in both varieties, "pissed off" means irritated).
Similarly, in AmE the word "pants" is the common word for the BrE "trousers" and "knickers" refers to a variety of half-length trousers (though most AmE users would use the term "shorts" rather than knickers), while the majority of BrE speakers would understand "pants" to mean "underpants" and "knickers" to mean "female underpants".
Sometimes the confusion is more subtle. In AmE the word "quite" used as a qualifier is generally a reinforcement, though it is somewhat uncommon in actual colloquial American use today and carries an air of formality: for example, "I'm quite hungry" is a very polite way to say "I'm very hungry". In BrE "quite" (which is much more common in conversation) may have this meaning, as in "quite right" or "quite mad", but it more commonly means "somewhat", so that in BrE "I'm quite hungry" can mean "I'm somewhat hungry". This divergence of use can lead to misunderstanding.
Different terms in different dialects.
Most speakers of American English are aware of some uniquely British terms. It is generally very easy to guess what some words, such as BrE "driving licence", mean, the AmE equivalent being "driver's license". However, use of many other British words such as "naff" (slang but commonly used to mean "not very good") are unheard of in American English.
Speakers of BrE are likely to understand most common AmE terms, examples such as "sidewalk (pavement or footpath)", "gas (gasoline/petrol)", "counterclockwise (anticlockwise)" or "elevator (lift)", without any problem, thanks in part to considerable exposure to American popular culture and literature. Certain terms that are heard less frequently, especially those likely to be absent or rare in American popular culture, e.g., "copacetic (very satisfactory)", are unlikely to be understood by most BrE speakers.
Other examples:
Holiday greetings.
It is increasingly common for Americans to say "Happy holidays", referring to all, or at least multiple, winter (in the Northern hemisphere) or summer (in the Southern hemisphere) holidays (Christmas, Hanukkah, Kwanzaa, etc.) especially when one's religious observances are not known; the phrase is rarely heard in the UK. In the UK, the phrases "holiday season" and "holiday period" refer to the period in the summer (in the Northern hemisphere) or winter (in the Southern hemisphere) when most people take time off from work, and travel; AmE does not use "holiday" in this sense, instead using "vacation" for recreational excursions.
In AmE, the prevailing Christmas greeting is "Merry Christmas", which is the traditional English Christmas greeting, as found in the English Christmas carol "We Wish You a Merry Christmas", and which appears several times in Charles Dickens' "A Christmas Carol". In BrE, "Happy Christmas" is a common alternative to "Merry Christmas".
Idiosyncratic differences.
Omission of "and" and "on".
Generally in British English, numbers with a value over one hundred have the word "and" inserted before the last two digits. For example, the number 115, when written in words or spoken aloud, would be "One hundred "and" fifteen", in British English. In American English, numbers are typically said or written in words in the same way, however if the word "and" is omitted ("One hundred fifteen"), this is also considered acceptable (in BrE this would be considered ungrammatical).
Likewise, in the US, the word "on" can be left out when referring to events occurring on any particular day of the week. The US possibility "The Cowboys won the game Saturday" would have the equivalent in the UK of "Sheffield United won the match on Saturday."
Figures of speech.
Both BrE and AmE use the expression "I couldn't care less", to mean that the speaker does not care at all. Some Americans use "I could care less" to mean the same thing. This variant is frequently derided as sloppy, as the literal meaning of the words is that the speaker "does" care to some extent.
In both areas, saying, "I don't mind" often means, "I'm not annoyed" (for example, by someone's smoking), while "I don't care" often means, "The matter is trivial or boring". However, in answering a question such as "Tea or coffee?", if either alternative is equally acceptable an American may answer, "I don't care", while a British person may answer, "I don't mind". Either can sound odd, confusing, or rude, to those accustomed to the other variant.
"To be "all set"" in both BrE and AmE can mean "to be prepared or ready", though it appears to be more common in AmE. It can also have an additional meaning in AmE of "to be finished or done", for example, a customer at a restaurant telling a waiter "I'm all set. I'll take the check."
Equivalent idioms.
A number of English idioms that have essentially the same meaning show lexical differences between the British and the American version; for instance:
 In the US, a "carpet" typically refers to a fitted carpet, rather than a rug.
Social and cultural differences.
Lexical items that reflect separate social and cultural development.
Education.
Primary and secondary school.
The US has a more uniform nationwide system of terms than does the UK, but the division by grades varies somewhat among the states and even among local school districts. For example, "elementary school" often includes kindergarten and may include sixth grade, with "middle school" including only two grades or extending to ninth grade. 
In the UK, the US equivalent of a "high school" is often referred to as a "secondary school" regardless of whether it is state funded or private. US Secondary education also includes "middle school" or "junior high school", a two- or three-year transitional school between elementary school and high school. "Middle school" is sometimes used in the UK as a synonym for the younger "junior school", covering the second half of the primary curriculum, current years four to six in some areas. However, in Dorset (South England), it is used to describe the second school in the three-tier system, which is normally from year 5 to year 8 . In other regions, such as Evesham and the surrounding area in Worcestershire, the second tier goes from year 6 to year 8, and both starting secondary school in year nine. In Kirklees, West Yorkshire, in the villages of the Dearne Valley there is a three tier system: first schools year reception to year five, middle school (Scissett/Kirkburton Middle School) year 6 to year 8 and high school ()year 9 to year 13.
A "public school" has opposite meanings in the two countries. In AmE this is a government-owned institution open to all students, supported by public funding. The BrE use of the term is in the context of "private" education: to be educated privately with a tutor. In England and Wales the term strictly refers to an ill-defined group of prestigious private independent schools funded by students' fees, although it is often more loosely used to refer to any independent school. Independent schools are also known as "private schools", and the latter is the term used in Scotland and Northern Ireland for all such fee-funded schools. Strictly, the term "public school" is not used in Scotland and Northern Ireland in the same sense as in England, but nevertheless Gordonstoun, the Scottish private school, is sometimes referred to as a "public school", as are some other Scottish private schools. Government-funded schools in Scotland and Northern Ireland are properly referred to as "state schools" but are sometimes confusingly referred to as "public schools" (with the same meaning as in the US), and in the US, where most public schools are administered by local governments, a "state school" typically refers to a college or university run by one of the U.S. states. 
Speakers in both the United States and the United Kingdom use several additional terms for specific types of secondary school. A US "prep school" or "preparatory school" is an independent school funded by tuition fees; the same term is used in the UK for a private school for pupils under 13, designed to prepare them for fee-paying public schools. In the US, "Catholic schools" cover costs through tuition and have affiliations with a religious institution, most often a Catholic church or diocese. In England, where the state-funded education system grew from parish schools organised by the local established church, the Church of England (C of E, or CE), and many schools, especially primary schools (up to age 11) retain a church connection and are known as "church schools", "CE schools" or "CE (aided) schools". There are also "faith schools" associated with the Roman Catholic Church and other major faiths, with a mixture of funding arrangements. 
In the US, a "magnet school" receives government funding and has special admission requirements: in some cases pupils gain admission through superior performance on admission tests, while other magnet schools admit students through a lottery. The UK has city academies, which are independent privately sponsored schools run with public funding and which can select up to 10% of pupils by aptitude. Moreover, in the UK 36 local education authorities retain selection by ability at 11. They maintain grammar schools (state funded secondary schools), which admit pupils according to performance in an examination (known as the 11+) and comprehensive schools that take pupils of all abilities. Grammar schools select the most academically able 10% to 23% of those who sit the exam. Students who fail the exam go to a secondary modern school, sometimes called a "high school", or increasingly an "academy". In areas where there are no grammar schools the comprehensives likewise may term themselves high schools or academies. Nationally only 6% of pupils attend grammar schools, mainly in four distinct counties. Some private schools are called "grammar schools", chiefly those that were grammar schools long before the advent of state education.
University.
In the UK a university student is said to "study", to "read" or, informally, simply to "do" a subject. In the recent past the expression 'to read a subject' was more common at the older universities such as Oxford and Cambridge. In the US a student "studies" or "majors in" a subject (although a student's "major", "concentration" or, less commonly, "emphasis" is also used in US colleges or universities to refer to the major subject of study). "To major in" something refers to the student's principal course of study; "to study" may refer to any class being taken. 
BrE: 
AmE: 
At university level in BrE, each "module" is taught or facilitated by a "lecturer" or "tutor"; "professor" is the job-title of a senior academic (in AmE, at some universities, the equivalent of the BrE lecturer is instructor, especially when the teacher has a lesser degree or no university degree, though the usage may become confusing according to whether the subject being taught is considered technical or not; it is also different from adjunct instructor/professor). In AmE each "class" is generally taught by a "professor" (although some US tertiary educational institutions follow the BrE usage), while the position of "lecturer" is occasionally given to individuals hired on a temporary basis to teach one or more classes and who may or may not have a doctoral degree. 
The word "course" in American use typically refers to the study of a restricted topic or individual subject (for example, "a course in Early Medieval England", "a course in integral calculus") over a limited period of time (such as a semester or term) and is equivalent to a "module" or sometimes "unit" at a British university. In the UK, a "course of study" or simply "course" is likely to refer to the entire programme of study, which may extend over several years and be made up of any number of "modules," hence it is also practically synonymous to a degree programme. A few university-specific exceptions exist: for example, at Cambridge the word "paper" is used to refer to a "module", while the whole course of study is called "tripos". 
A "dissertation" in AmE refers to the final written product of a doctoral student to fulfil the requirement of that program. In BrE, the same word refers to the final written product of a student in an undergraduate or taught master's programme. A dissertation in the AmE sense would be a thesis in BrE, though "dissertation" is also used. 
Another source of confusion is the different usage of the word "college". (See a full international discussion of the various meanings at college.) In the US, it refers to a post-high school institution that grants either associate's or bachelor's degrees, and in the UK, it refers to any post-secondary institution that is not a university (including "sixth form college" after the name in secondary education for years 12 and 13, the "sixth form") where intermediary courses such as A levels or NVQs can be taken and GCSE courses can be retaken. College may sometimes be used in the UK or in Commonwealth countries as part of the name of a secondary or high school (for example, Dubai College). In the case of Oxford, Cambridge, Aberdeen, London, Lancaster, Durham, Kent and York universities, all members are also members of a college which is part of the university, for example, one is a member of King's College, Cambridge and hence the university. 
In both the US and UK "college" can refer to some division within a university that comprises related academic departments such as the "college of business and economics" though in the UK "faculty" is more often used. Institutions in the US that offer two to four years of post-high school education often have the word "college" as part of their name, while those offering more advanced degrees are called a "university". (There are exceptions: Boston College, Dartmouth College and the College of William & Mary are examples of colleges that offer advanced degrees, while Vincennes University is an unusual example of a "university" that offers only associate degrees in the vast majority of its academic programs.) American students who pursue a "bachelor's degree" (four years of higher education) or an "associate degree" (two years of higher education) are "college students" regardless of whether they attend a college or a university and refer to their educational institutions informally as "colleges." A student who pursues a master's degree or a doctorate degree in the arts and sciences is in AmE a "graduate student"; in BrE a "postgraduate student" although "graduate student" is also sometimes used. Students of advanced professional programs are known by their field ("business student", "law student", "medical student"). Some universities also have a residential college system, the details of which may vary but generally involve common living and dining spaces as well as college-organised activities. Nonetheless, when it comes to the level of education, AmE generally uses the word "college" (e.g., going to college) whereas BrE generally uses the word "university" (e.g., going to university) regardless of the institution's official designation/status in both countries. 
In the context of higher education, the word "school" is used slightly differently in BrE and AmE. In BrE, except for the University of London, the word school is used to refer to an academic department in a university. In AmE, the word school is used to refer to a collection of related academic departments and is headed by a dean. When it refers to a division of a university, school is practically synonymous to a college. 
"Professor" has different meanings in BrE and AmE. In BrE it is the highest academic rank, followed by reader, senior lecturer and lecturer. In AmE "professor" refers to academic staff of all ranks, with (full) professor (largely equivalent to the UK meaning) followed by associate professor and assistant professor. 
"Tuition" has traditionally had separate meaning in each variation. In BrE it is the educational content transferred from teacher to student at a university. In AmE it is the money (the fees) paid to receive that education (BrE: tuition fees).
General terms.
In both the US and the UK, a student "takes" an exam, but in BrE a student can also be said to "sit" an exam. When preparing for an exam students "revise" (BrE)/"review" (AmE) what they have studied; the BrE idiom "to revise for" has the equivalent "to review for" in AmE. 
Examinations are supervised by "invigilators" in the UK and "proctors" (or "(exam) supervisors") in the US (a "proctor" in the UK is an official responsible for student discipline at the University of Oxford or Cambridge). In the UK a teacher first "sets" and then "administers" exam, while in the US, a teacher first "writes", "makes", "prepares", etc. and then "gives" an exam. With the same basic meaning of the latter idea but with a more formal or official connotation, a teacher in the US may also "administer" or "proctor" an exam. 
BrE: 
AmE: 
In BrE, students are awarded "marks" as credit for requirements (e.g., tests, projects) while in AmE, students are awarded "points" or "grades" for the same. Similarly, in BrE, a candidate's work is being "marked", while in AmE it is said to be "graded" to determine what mark or grade is given. 
There is additionally a difference between American and British usage in the word "school". In British usage "school" by itself refers only to primary (elementary) and secondary (high) schools and to "sixth forms" attached to secondary schools—if one "goes to school", this type of institution is implied. By contrast an American student at a university may be "in/at school", "coming/going to school", etc. US and British law students and medical students both commonly speak in terms of going to "law school" and "med[ical] school", respectively. However, the word "school" is used in BrE in the context of higher education to describe a division grouping together several related subjects within a university, for example a "School of European Languages" containing "departments" for each language and also in the term "art school". It is also the name of some of the constituent colleges of the University of London, for example, School of Oriental and African Studies, London School of Economics. 
Among high-school and college students in the United States, the words "freshman" (or the gender-neutral terms "first year" or sometimes "freshie"), "sophomore", "junior" and "senior" refer to the first, second, third, and fourth years respectively. It is important that the context of either high school or college first be established or else it must be stated directly (that is, "She is a high-school freshman". "He is a college junior."). Many institutes in both countries also use the term "first-year" as a gender-neutral replacement for "freshman", although in the US this is recent usage, formerly referring only to those in the first year as a graduate student. One exception is the University of Virginia; since its founding in 1819 the terms "first-year", "second-year", "third-year", and "fourth-year" have been used to describe undergraduate university students. At the United States service academies, at least those operated by the federal government directly, a different terminology is used, namely "fourth class", "third class", "second class" and "first class" (the order of numbering being the reverse of the number of years in attendance). In the UK first-year university students are sometimes called "freshers" early in the academic year; however, there are no specific names for those in other years nor for school pupils. Graduate and professional students in the United States are known by their year of study, such as a "second-year medical student" or a "fifth-year doctoral candidate." Law students are often referred to as "1L", "2L", or "3L" rather than "nth-year law students"; similarly, medical students are frequently referred to as "M1", "M2", "M3", or "M4". 
While anyone in the US who finishes studying at any educational institution by passing relevant examinations is said to "graduate" and to be a "graduate", in the UK only degree and above level students can "graduate". "Student" itself has a wider meaning in AmE, meaning any person of any age studying any subject at any level (including those not doing so at an educational institution, such as a "piano student" taking private lessons in a home), whereas in BrE it tends to be used for people studying at a post-secondary educational institution and the term "pupil" is more widely used for a young person at primary or secondary school, though the use of "student" for secondary school pupils in the UK is increasingly used, particularly for "sixth form" (years 12 and 13). 
The names of individual institutions can be confusing. There are several high schools with the word "university" in their names in the United States that are not affiliated with any post-secondary institutions and cannot grant degrees, and there is one public high school, Central High School of Philadelphia, that does grant bachelor's degrees to the top ten per cent of graduating seniors. British secondary schools occasionally have the word "college" in their names. 
When it comes to the admissions process, applicants are usually asked to solicit "letters of reference" or reference forms from referees in BrE. In AmE, these are called "letters of recommendation" or recommendation forms. Consequently, the writers of these letters are known as "referees" and "recommenders", respectively by country. In AmE, the word "referee" is nearly always understood to refer to an umpire of a sporting match. 
In the context of education, for AmE, the word "staff" mainly refers to school personnel who are neither administrators nor have teaching loads or academic responsibilities; personnel who have academic responsibilities are referred to as members of their institution's "faculty." In BrE, the word "staff" refers to both academic and non-academic school personnel. As mentioned previously, the term "faculty" in BrE refers more to a collection of related academic departments.
Government and politics.
In the UK, political candidates "stand for election", while in the US, they "run for office". There is virtually no crossover between BrE and AmE in the use of these terms. Also, the document which contains a party's positions/principles is referred to as a "party platform" in AmE, whereas it is in BrE commonly known as a "party manifesto". (In AmE, using the term "manifesto" may connote that the party is an extremist or radical organisation.) The term "general election" is used slightly differently in British and American English. In BrE, it refers exclusively to a nationwide parliamentary election and is differentiated from local elections (mayoral and council), EU Parliamentary elections and by-elections; whereas in AmE, it refers to a final election for any government position in the US, where the term is differentiated from the term "primary" (an election that determines a party's candidate for the position in question). Additionally, a "by-election" in BrE is called a "special election" in AmE.
In AmE, the term "swing state", "swing county", "swing district" is used to denote a jurisdiction/constituency where results are expected to be close but crucial to the overall outcome of the general election. In BrE, the term "marginal constituency" is more often used for the same and "swing" is more commonly used to refer to how much one party has gained (or lost) an advantage over another compared to the previous election. 
In the UK, the term "government" only refers to what is commonly known in America as the "executive branch" or the particular "administration".
A local government in the UK is generically referred to as the "council," whereas in the United States a local government will be generically referred to as the "City" (or county, village, etc., depending on what kind of entity the government serves).
Business and finance.
In financial statements, what is referred to in AmE as "revenue" or "sales" is known in BrE as "turnover." In AmE, having "high turnover" in a business context would generally carry negative implications, though the precise meaning would differ by industry. 
A bankrupt firm "goes into administration" or liquidation in BrE; in AmE it "goes bankrupt", or "files for Chapter 7" (liquidation) or "Chapter 11" (reorganisation). An insolvent individual or partnership "goes bankrupt" in both BrE and AmE. 
If a finance company takes possession of a mortgaged property from a debtor, it is called "foreclosure" in AmE and "repossession" in BrE. In some limited scenarios, "repossession" may be used in AmE, but it is much less commonly compared to "foreclosure". One common exception in AmE is for automobiles, which are always said to be "repossessed". Indeed, an agent who collects these cars for the bank is colloquially known in AmE as a "repo man".
Employment and recruitment.
In BrE, the term "curriculum vitae" (commonly abbreviated to "CV") is used to describe the document prepared by applicants containing their credentials required for a job. In AmE, the term "resume" is more commonly used, with "CV" primarily used in academic or research contexts, and is usually more comprehensive than a "resume".
Insurance.
AmE distinguishes between "coverage" as a noun and "cover" as a verb; an American seeks to buy enough insurance coverage in order to adequately cover a particular risk. BrE uses the word "cover" for both the noun and verb forms.
Transport.
AmE speakers refer to "transportation" and BrE speakers to "transport". ("Transportation" in the UK has traditionally meant the punishment of criminals by deporting them to an overseas penal colony.) In AmE, the word "transport" is usually used only as a verb, seldom as a noun or adjective except in reference to certain specialised objects, such as a "tape transport" or a "military transport" (e.g., a troop transport, a kind of vehicle, not an act of transporting).
Road transport.
Differences in terminology are especially obvious in the context of roads. The British term "dual carriageway", in American parlance, would be "divided highway" or perhaps, simply "highway". The "central reservation" on a "motorway" or "dual carriageway" in the UK would be the "median" or "center divide" on a "freeway", "expressway", "highway" or "parkway" in the US. The one-way lanes that make it possible to enter and leave such roads at an intermediate point without disrupting the flow of traffic are known as "slip roads" in the UK but in the US, they are typically known as "ramps" and both further distinguish between "on-ramps" or "on-slips" (for entering onto a highway/carriageway) and "off-ramps" or "exit-slips" (for leaving a highway/carriageway). When American engineers speak of "slip roads", they are referring to a street that runs alongside the main road (separated by a berm) to allow off-the-highway access to the premises that are there; however, the term "frontage road" is more commonly used, as this term is the equivalent of "service road" in the UK. However, it is not uncommon for an American to use "service road" as well instead of "frontage road".
In the UK, the term "outside lane" refers to the higher-speed "overtaking lane" ("passing lane" in the US) closest to the centre of the road, while "inside lane" refers to the lane closer to the edge of the road. In the US, "outside lane" is used only in the context of a turn, in which case it depends in which direction the road is turning (i.e., if the road bends right, the left lane is the "outside lane", but if the road bends left, it is the right lane). Both also refer to "slow" and "fast" lanes (even though all actual traffic speeds may be at or around the legal speed limit). 
In the UK "drink driving" refers to driving after having consumed alcoholic beverages, while in the US, the term is "drunk driving". The legal term in the US is "driving while intoxicated" (DWI) or "driving under the influence (of alcohol)" (DUI). The equivalent legal phrase in the UK is "drunk in charge of a motor vehicle" (DIC) or more commonly "driving with excess alcohol". 
In the UK, a hire car is the US equivalent of a rental car. The term "hired car" can be especially misleading for those in the US, where the term "hire" is generally only applied to the employment of people and the term "rent" is applied to the temporary custody of goods. To an American, "hired car" would imply that the car has been brought into the employment of an organisation as if it were a person, which would sound nonsensical. 
In the UK, a saloon is a vehicle that is equivalent to the American sedan. This is particularly confusing to Americans, because in the US the term "saloon" is used in only one context: describing an old bar (UK pub) in the American West (a Western saloon). "Coupé" is used by both to refer to a two-door car, but is usually pronounced with two syllables in the UK (coo-pay) and one syllable in the US (coop). 
In the UK, "van" may refer to a lorry (UK) of any size, whereas in the US, "van" is only understood to be a very small, boxy truck (US) (such as a "moving van") or a long passenger automobile with several rows of seats (such as a "minivan"). A large, long vehicle used for cargo transport would nearly always be called a "truck" in the US, though alternate terms such as "eighteen-wheeler" may be occasionally heard (regardless of the actual number of tires on the truck). 
In the UK, a silencer is the equivalent to the US muffler. In the US, the word silencer has only one meaning: an attachment on the barrel of a gun designed to stop the distinctive crack of a gunshot. 
Specific auto parts and transport terms have different names in the two dialects, for example:<br>
Rail transport.
There are also differences in terminology in the context of rail transport. The best known is "railway" in the UK and "railroad" in America, but there are several others. A "railway station" in the UK is a "railroad station" or "train station" in the US; trains have "drivers" (often called "engine drivers") in the UK, while in America trains are driven by "engineers"; trains have "guards" in the UK and "conductors" in the US; a place where two tracks meet is called a set of "points" in the UK and a "switch" in the US; and a place where a road crosses a railway line at ground level is called a "level crossing" in the UK and a "grade crossing" or "railroad crossing" in America. In the UK, the term "sleeper" is used for the devices that bear the weight of the rails and are known as "ties" or "crossties" in the United States. In a rail context, "sleeper" (more often, "sleeper car") would be understood in the US as a rail car with sleeping quarters for its passengers. The British term "platform" in the sense "The train is at Platform 1" would be known in the US by the term "track", and used in the phrase "The train is on Track 1". The British term "brake van" or "guard's van" is a "caboose" in the US. The American English phrase "All aboard!" when boarding a train is rarely used in the UK, and when the train reaches its final stop, in the UK the phrase used by rail personnel is "All change!" while in the US it is "All out!"
Television.
Traditionally, a "show" on British television would have referred to a light-entertainment program (BrE "programme") with one or more performers and a participative audience, whereas in American television, the term is used for any type of program. British English traditionally referred to other types of program by their type, such as drama, serial etc., but the term "show" has now taken on the generalised American meaning. In American television the episodes of a program first broadcast in a particular year constitute a "season", while the entire run of the program—which may span several seasons—is called a "series". In British television, on the other hand, the word "series" may apply to the episodes of a program in one particular year, for example, "The 1998 series of "Grange Hill"", as well as to the entire run. However, the entire run may occasionally be referred to as a "show".
The term "telecast", meaning television broadcast and uncommon even in the US, is not used in British English. A television program would be "broadcast", "aired" or "shown" in both the UK and US.
Telecommunications.
A long-distance call is a "trunk call" in British English, but is a "toll call" in American English, though neither term is well known among younger Americans. The distinction is a result of historical differences in the way local service was billed; the Bell System traditionally flat-rated local calls in all but a few markets, subsidising local service by charging higher rates, or tolls, for intercity calls, allowing local calls to appear to be free. British Telecom (and the British Post Office before it) charged for all calls, local and long distance, so labelling one class of call as "toll" would have been meaningless. 
Similarly, a toll-free number in America is a freephone number in the UK. The term "freefone" is a BT trademark.
Rivers.
In Britain rivers are referred to using the format: River Thames. Americans generally use the Thames River format.
Style.
Use of "that" and "which" in restrictive and non-restrictive relative clauses.
Generally, a non-restrictive relative clause (also called non-defining or supplementary) is one containing information that is supplementary, i.e. does not change the meaning of the rest of the sentence, while a restrictive relative clause (also called defining or integrated) contains information essential to the meaning of the sentence, effectively limiting the modified noun phrase to a subset that is defined by the relative clause.
An example of a restrictive clause is "The dog that bit the man was brown."
An example of a non-restrictive clause is "The dog, which bit the man, was brown."
In the former, "that bit the man" identifies which dog the statement is about.
In the latter, "which bit the man" provides supplementary information about a known dog.
A non-restrictive relative clause is typically set off by commas, whereas a restrictive relative clause is not, but this is not a rule that is universally observed. In speech, this is also reflected in the intonation.
Writers commonly use "which" to introduce a non-restrictive clause, and "that" to introduce a restrictive clause. "That" is rarely used to introduce a non-restrictive relative clause in prose. "Which" and "that" are both commonly used to introduce a restrictive clause; a study in 1977 reported that about 75 per cent of occurrences of "which" were in restrictive clauses.
H. W. Fowler, in "A Dictionary of Modern English Usage" of 1926, followed others in suggesting that it would be preferable to use "which" as the non-restrictive (what he calls "non-defining") pronoun and "that" as the restrictive (what he calls defining) pronoun, but he also stated that this rule was observed neither by most writers nor by the best writers. 
He implied that his suggested usage was more common in American English.
Fowler notes that his recommended usage presents problems, in particular that "that" must be the first word of the clause, which means, for instance, that "which" cannot be replaced by "that" when it immediately follows a preposition (e.g. "the basic unit "from which" matter is constructed") – though this would not prevent a stranded preposition (e.g. "the basic unit "that" matter is constructed "from"").
Style guides by American prescriptivists, such as Bryan Garner, typically insist, for stylistic reasons, that "that" be used for restrictive relative clauses and "which" be used for non-restrictive clauses, referring to the use of "which" in restrictive clauses as a "mistake". 
According to the 2015 edition of "Fowler's Dictionary of Modern English Usage", "In AmE "which" is 'not generally used in restrictive clauses, and that fact is then interpreted as the absolute rule that only "that" may introduce a restrictive clause', whereas in BrE 'either "that" or "which" may be used in restrictive clauses', but many British people 'believe that "that" is obligatory'".
Writing.
Spelling.
Before the early 18th century English spelling was not standardised. Different standards became noticeable after the publishing of influential dictionaries. For the most part current BrE spellings follow those of Samuel Johnson's "Dictionary of the English Language" (1755), while AmE spellings follow those of Noah Webster's "An American Dictionary of the English Language" (1828). In the United Kingdom, the influences of those who preferred the French spellings of certain words proved decisive. In many cases AmE spelling deviated from mainstream British spelling; on the other hand it has also often retained older forms. Many of the now characteristic AmE spellings were popularised, although often not created, by Noah Webster. Webster chose already-existing alternative spellings "on such grounds as simplicity, analogy or etymology". Webster did attempt to introduce some reformed spellings, as did the Simplified Spelling Board in the early 20th century, but most were not adopted. Later spelling changes in the UK had little effect on present-day US spelling, and vice versa.
Punctuation.
Full stops and periods in abbreviations.
There have been some trends of transatlantic difference in use of periods in some abbreviations. These are discussed at "Abbreviation § Periods (full stops) and spaces". Unit symbols such as kg and Hz are never punctuated.
Parentheses/brackets.
In British English, "( )" marks are often referred to as brackets, whereas "[ ]" are called square brackets and "{ }" are called curly brackets. In formal British English and in American English "( )" marks are parentheses (singular: parenthesis), "[ ]" are called brackets or square brackets, and "{ }" can be called either curly brackets or braces. Despite the different names, these marks are used in the same way in both dialects.
Quoting.
British and American English differ in the preferred quotation mark style, including the placement of commas and periods. In American English, " and ' are called quote marks, whereas in British English, " and ' are referred to as either inverted commas or speech marks. Additionally, in American English direct speech typically uses the double quote mark ( " ), whereas in British English it is common to use the inverted comma ( ' ).
Commas in headlines.
American newspapers commonly use a comma as a shorthand for "and" in headlines. For example, "The Washington Post" had the headline "A TRUE CONSERVATIVE: For McCain, Bush Has Both Praise, Advice."
Numerical expressions.
There are many differences in the writing and speaking of English numerals, most of which are matters of style, with the notable exception of different definitions for billion.
The two countries have different conventions for floor numbering. The UK uses a mixture of the metric system and Imperial units, where in the US, United States customary units are dominant in everyday life with a few fields using the metric system.
Monetary amounts.
Monetary amounts in the range of one to two major currency units are often spoken differently. In AmE one may say "a dollar fifty" or "a pound eighty", whereas in BrE these amounts would be expressed "one dollar fifty" and "one pound eighty". For amounts over a dollar an American will generally either drop denominations or give both dollars and cents, as in "two-twenty" or "two dollars and twenty cents" for $2.20. An American would not say "two dollars twenty". On the other hand, in BrE, "two-twenty" or "two pounds twenty" would be most common.
It is more common to hear a British-English speaker say "one thousand two hundred dollars" than "a thousand and two hundred dollars", although the latter construct is common in AmE. In British English, the "and" comes after the hundreds ("one thousand, two hundred and thirty dollars"). The term "twelve hundred dollars", popular in AmE, is frequently used in BrE but only for exact multiples of 100 up to 1,900. Speakers of BrE very rarely hear amounts over 1,900 expressed in hundreds, for example, "twenty-three hundred". In AmE it would not be unusual to refer to a high, uneven figure such as 2,307 as "twenty-three hundred and seven".
In BrE, particularly in television or radio advertisements, integers can be pronounced individually in the expression of amounts. For example, "on sale for £399" might be expressed "on sale for three nine nine", though the full "three hundred and ninety-nine pounds" is at least as common. An American advertiser would almost always say "on sale for three ninety-nine", with context distinguishing $399 from $3.99. In British English the latter pronunciation implies a value in pounds and pence, so "three ninety-nine" would be understood as £3.99.
In spoken BrE the word "pound" is sometimes colloquially used for the plural as well. For example, "three pound forty" and "twenty pound a week" are both heard in British English. Some other currencies do not change in the plural; yen and rand being examples. This is in addition to normal adjectival use, as in "a twenty-pound-a-week pay-rise" (US "raise"). The euro most often takes a regular plural "-s" in practice despite the EU dictum that it should remain invariable in formal contexts; the invariable usage is more common in Ireland, where it is the official currency.
In BrE the use of "p" instead of "pence" is common in spoken usage. Each of the following has equal legitimacy: "3 pounds 12 p"; "3 pounds and 12 p"; "3 pounds 12 pence"; "3 pounds and 12 pence"; as well as just "8 p" or "8 pence". In everyday usage the amount is simply read as figures (£3.50 = three pounds fifty) as in AmE.
AmE uses words such as "nickel", "dime", and "quarter" for small coins. In BrE the usual usage is "a 10-pence piece" or "a 10p piece" or simply "a 10p", for any coin below £1, "pound coin" and "two-pound coin". BrE did have specific words for a number of coins before decimalisation. Formal coin names such as "half crown" (2/6) and "florin" (2/-), as well as slang or familiar names such as "bob" (1/-) and "tanner" (6d) for pre-decimalization coins are still familiar to older BrE speakers but they are not used for modern coins. In older terms like "two-bob bit" (2/-) and "thrupenny bit" (3d), the word "bit" had common usage before decimalisation similar to that of "piece" today.
In order to make explicit the amount in words on a check (BrE "cheque"), Americans write "three and " (using this solidus construction or with a horizontal division line): they do not need to write the word "dollars" as it is usually already printed on the check. On a cheque UK residents would write "three pounds and 24 pence", "three pounds ‒ 24", or "three pounds ‒ 24p" since the currency unit is not preprinted. To make unauthorised amendment difficult, it is useful to have an expression terminator even when a whole number of dollars/pounds is in use: thus, Americans would write "three and " or "three and " on a three-dollar check (so that it cannot easily be changed to, for example, "three million"), and UK residents would write "three pounds only".
Dates.
Dates are usually written differently in the short (numerical) form. Christmas Day 2000, for example, is 25/12/00 or 25.12.00 in the UK and 12/25/00 in the US, although the formats 25/12/2000, 25.12.2000, and 12/25/2000 now have more currency than they had before Y2K. Occasionally other formats are encountered, such as the ISO 8601 2000-12-25, popular among programmers, scientists and others seeking to avoid ambiguity, and to make alphanumerical order coincide with chronological order. The difference in short-form date order can lead to misunderstanding, especially when using software or equipment that uses the foreign format. For example, 06/04/05 could mean either June 4, 2005 (if read as US format), 6 April 2005 (if seen as in UK format) or even 5 April 2006 if taken to be an older ISO 8601-style format where 2-digit years were allowed.
When using the name of the month rather than the number to write a date in the UK, the recent standard style is for the day to precede the month, e. g., 21 April. Month preceding date is almost invariably the style in the US, and was common in the UK until the late twentieth century. British usage often changes the day from an integer to an ordinal, i.e., 21st instead of 21. In speech, "of" and "the" are used in the UK, as in "the 21st of April". In written language, the words "the" and "of" may be and are usually dropped, i.e., 21 April. The US would say this as "April 21st", and this form is still common in the UK. One of the few exceptions in American English is saying "the Fourth of July" as a shorthand for the United States Independence Day. In the US military the British forms are used, but the day is read cardinally, while among some speakers of New England and Southern American English varieties and who come from those regions but live elsewhere, those forms are common, even in formal contexts.
Phrases such as the following are common in the UK but are generally unknown in the US: "A week today", "a week tomorrow", "a week Tuesday" and "Tuesday week"; these all refer to a day more than a week in the future. "A fortnight Friday" and "Friday fortnight" refer to a day two weeks after the coming Friday). "A week on Tuesday" and "a fortnight on Friday" could refer either to a day in the past ("it's a week on Tuesday, you need to get another one") or in the future ("see you a week on Tuesday"), depending on context. In the US the standard construction is "a week from today", "a week from tomorrow", etc. BrE speakers may also say "Thursday last" or "Thursday gone" where AmE would prefer "last Thursday". "I'll see you (on) Thursday coming" or "let's meet this coming Thursday" in BrE refer to a meeting later this week, while "not until Thursday next" would refer to next week. In BrE there is also common use of the term 'Thursday after next' or 'week after next' meaning 2 weeks in the future and 'Thursday before last' and 'week before last' meaning 2 weeks in the past, but not when referring to times more than 2 weeks been or gone or when using the terms tomorrow today or yesterday then in BrE you would say '5 weeks on Tuesday' or '2 weeks yesterday'.
Time.
The 24-hour clock ("18:00", "18.00" or "1800") is considered normal in the UK and Europe in many applications including air, rail and bus timetables; it is largely unused in the US outside military, police, aviation and medical applications. As a result, many Americans refer to the 24-hour clock as "military time". Some British English style guides recommend the full stop (.) when telling time, compared to American English which uses colons (:) (i.e., 11:15 PM or 23:15 for AmE and 11.15 pm or 23.15 for BrE). Usually in the military (and sometimes in the police, aviation and medical) applications on both sides of the Atlantic "0800" and "1800" are read as ("oh/zero") "eight hundred" and "eighteen hundred" hours respectively.
Fifteen minutes after the hour is called "quarter past" in British usage and "a quarter after" or, less commonly, "a quarter past" in American usage. Fifteen minutes before the hour is usually called "quarter to" in British usage and "a quarter of", "a quarter to" or "a quarter 'til" in American usage; the form "a quarter to" is associated with parts of the Northern United States, while "a quarter 'til" is found chiefly in the Appalachian region. Thirty minutes after the hour is commonly called "half past" in both BrE and AmE; "half after" used to be more common in the US. In informal British speech, the preposition is sometimes omitted, so that 5:30 may be referred to as "half five"; this construction is entirely foreign to US speakers, who would possibly interpret "half five" as 4:30 (halfway to 5:00) rather than 5:30. The AmE formations "top of the hour" and "bottom of the hour" are not used in BrE. Forms such as "eleven forty" are common in both dialects. To be simple and direct in telling time, no terms relating to fifteen or thirty minutes before/after the hour are used; rather the time is told exactly as for example "nine fifteen", "ten forty-five".
Other.
In sports statistics, certain percentages such as those for winning or win-loss records and saves in field or ice hockey and association football are almost always expressed as a decimal proportion to three places in AmE and are usually read aloud as if they are whole numbers, e.g. (0).500 or five hundred, hence the phrase "games/matches over five hundred", whereas in BrE they are also expressed but as true percentages instead, after multiplying the decimal by 100%, that is, 50% or "fifty per cent" and "games/matches over 50% or 50 per cent". However, "games/matches over 50% or 50 percent" is also found in AmE.
The American practice of expressing so-called percentages in sports statistics as decimals originated with baseball's batting averages, developed by English-born statistician and historian Henry Chadwick.
Demographics.
Linguist Braj Kachru, quoted by "The Christian Science Monitor" in 1996, stated that "American English is spreading faster than British English". The "Monitor" stated that English taught in Europe and the Commonwealth is more British-influenced, while English taught in Latin America is more American-influenced; however, most English use outside the classroom is more influenced by the United States: Americans greatly outnumber Britons; in addition, as of 1993, the United States originated 75 per cent of the world's TV programming. A BBC columnist assessed in 2015 that "American English is the current dominant force globally, like it or not".