Flat (music)

In music, flat (Italian bemolle for "soft B") means "lower in pitch". Flat is the opposite of sharp, which is a raising of pitch. In musical notation, flat means "lower in pitch by one semitone (half step)", notated using the symbol which is derived from a stylised lowercase 'b'. For instance, the music below has a key signature with three flats (indicating either E major or C minor) and the note, D, has a flat accidental.
\override Score.TimeSignature #'stencil = ##f
\relative c" {
 \clef treble \key es \major \time 4/4 des1
</score>
The Unicode character ♭ (U+266D) can be found in the block Miscellaneous Symbols; its HTML entity is &#9837;.
Under twelve-tone equal temperament, D for instance is enharmonically equivalent to C, and G is equivalent to F. In any other tuning system, such enharmonic equivalences in general do not exist. To allow extended just intonation, composer Ben Johnston uses a sharp as an accidental to indicate a note is raised 70.6 cents (ratio 25:24), and a flat to indicate a note is lowered 70.6 cents.
In intonation, flat can also mean "slightly lower in pitch" (by some unspecified amount). If two simultaneous notes are slightly out-of-tune, the lower-pitched one (assuming the higher one is properly pitched) is "flat" with respect to the other. Furthermore, the verb "flatten" means to lower the pitch of a note, typically by a small musical interval.
Key signatures.
Flats are used in the key signatures of
The order of flats in the key signatures of music notation, following the circle of fifths, is B, E, A, D, G, C and F (mnemonics for which include Battle Ends And Down Goes Charles' Father "and" Before Eating A Doughnut Get Coffee First).
Related symbols.
Double flats also exist, which look like (similar to two flats, ) and lower a note by two semitones, or a whole step. The Unicode character 𝄫 (U+1D12B) in the Musical Symbols block represents the double-flat sign. Historically, in order to raise a double flat to a simple flat, it was required to use the notation . In modern scores it is acceptable to simply denote this with a single flat .
\override Score.TimeSignature #'stencil = ##f
\relative c" {
 \clef treble \key c \major \time 4/4 beses2 bes2
</score>
A quarter-tone flat or half flat, indicating the use of quarter tones, may be marked with various symbols including a flat with a slash () or a reversed flat sign (). A three-quarter-tone flat, flat and a half or sesquiflat, is represented by a half flat and a regular flat ().
\override Score.TimeSignature #'stencil = ##f
\relative c" {
 \clef treble \key c \major \time 4/4 ceh1 deseh
} }</score>
Although very uncommon, a triple flat () can sometimes be found. It lowers a note three semitones.