In music notation, a flat (♭) is a symbol that lowers the pitch of a note by a half step (also known as a semitone). When a note is preceded by a flat, it signifies that you should play the note one half step lower than its natural pitch.
For example:
- If you have a B♭ (B flat), it is a half step lower than B.
- Similarly, an E♭ (E flat) is a half step lower than E.
In some contexts, a flat can also affect the surrounding notes, particularly if it appears in a key signature. In that case, all instances of the note corresponding to the flat in that key (throughout the piece) are automatically lowered by a half step unless otherwise indicated.