Flat (music)

From Conservapedia

In music, flat means that a given tone should be one semitone lower than usual. Thus, D-flat is one semitone below D. On a piano keyboard, the flat tones are the black keys.

In many cases, a flat note will be the same tone as the sharp note of the note below. For example, D-flat is the same tone as C-sharp. It is important to distinguish between them, however, since they will have different positions in the harmonic structure of the music.

In some rare cases, one will see a double flat. This means that the tone must be lowered by two semitones, or one full tone.

In musical notation, flat is indicated by the symbol '♭', and double flat by '♭♭'.