Defn: A character [] before a note, indicating a tone which is a half step or semitone lower.

9. (Geom.)

Defn: A homaloid space or extension.

FLAT
Flat, v. t. [imp. & p. p. Flatted; p. pr. & vb. n. Flatting.]

1. To make flat; to flatten; to level.

2. To render dull, insipid, or spiritless; to depress. Passions are allayed, appetites are flatted. Barrow.

3. To depress in tone, as a musical note; especially, to lower in pitch by half a tone.

FLAT
Flat, v. i.

1. To become flat, or flattened; to sink or fal to an even surface. Sir W. Temple.

2. (Mus.)