Totum pro parte

Totum pro parte is Latin for "the whole for a part"; it refers to a kind of metonymy. The plural is tota pro partibus, "wholes for parts". In a context of language, it means something is named after something of which it is only a part (or only a limited characteristic, not necessarily representative for the whole). A "pars pro toto" (in which a part is used to describe the whole) is the opposite of a "totum pro parte".
In geography.
Some place names of large areas are commonly used to refer synonymously to a smaller part of the larger area than is strictly deemed correct. Examples of this include:
Other examples.
The verb "to drink" is often used in this manner. Depending on context it can stand for the generic, standard definition "to consume a liquid" (e.g. "I'm thirsty, is there anything to drink?") or for the narrow, limited definition "to imbibe alcoholic beverages" (e.g. "He goes out to drink too often"). Also, "fluid" can be used for "liquid", as in "brake fluid" or "bodily fluid". (The presence of air, a fluid, is not wanted when there is "low fluid".)
The "Internet" for the "World Wide Web (WWW)"; the Internet is a network of computer networks, whereas the WWW is a network of hypertext documents that one accesses via the Internet.
When someone asks, "Is it a PC or a Mac?", they are actually asking whether it's a PC (personal computer) running the Microsoft Windows operating system, or one of a line of PCs made by Apple called a "Mac". A PC is in fact any computer used for personal purposes, and can effectively be running one of many different operating systems.
In the United States, "Congress" is used to refer to the legislative body of the government, including both the House of Representatives (the "House)" and the Senate. The term "congressman" or "congresswoman" means "member of the House (of Representatives)". 
An athletic team is often called by the name of the whole (e.g. a city, country or organization) it represents: 
When people talk about "the summer", they very often mean just the summer vacation period (often from six weeks to 2-3 months, depending on the place) and not necessarily the whole summer season.
In pharmacies in Quebec, the prescription plan of the Régie de l'assurance maladie du Québec (RAMQ) is often referred to just as RAMQ, even though the RAMQ is the government health insurance board of Quebec and as such makes provincial health insurance cards (among other things).