adjective / noun

flat

A semitone below the natural pitch.

The melody begins on B flat.

Etymology

Old Norse flatr meant level or flat. Music applies the downward image of flattening to a lowered note, specifying a pitch one semitone below its natural form.

More examples

She marked a flat before the note.
Two flats appeared in the key signature.
The singer's final note was slightly flat.

Forms

flat · flats

Similar words

sharp: A semitone above the natural pitch rather than below.
natural: The pitch without a sharp or flat alteration.