1. (superl.) Having an even and horizontal surface, or nearly so, without prominences or depressions; level without inclination; plane.

2. (superl.) Lying at full length, or spread out, upon the ground; level with the ground or earth; prostrate; as, to lie flat on the ground; hence, fallen; laid low; ruined; destroyed.

3. (superl.) Wanting relief; destitute of variety; without points of prominence and striking interest.

4. (superl.) Tasteless; stale; vapid; insipid; dead; as, fruit or drink flat to the taste.

5. (superl.) Unanimated; dull; uninteresting; without point or spirit; monotonous; as, a flat speech or composition.

6. (superl.) Lacking liveliness of commercial exchange and dealings; depressed; dull; as, the market is flat.

7. (superl.) Clear; unmistakable; peremptory; absolute; positive; downright.

8. (superl.) Below the true pitch; hence, as applied to intervals, minor, or lower by a half step; as, a flat seventh; A flat.

9. (superl.) Not sharp or shrill; not acute; as, a flat sound.

10. (superl.) Sonant; vocal; -- applied to any one of the sonant or vocal consonants, as distinguished from a nonsonant (or sharp) consonant.

11. (adv.) In a flat manner; directly; flatly.

12. (adv.) Without allowance for accrued interest.

13. (n.) A level surface, without elevation, relief, or prominences; an extended plain; specifically, in the United States, a level tract along the along the banks of a river; as, the Mohawk Flats.

14. (n.) A level tract lying at little depth below the surface of water, or alternately covered and left bare by the tide; a shoal; a shallow; a strand.

15. (n.) Something broad and flat in form

16. (n.) A flat-bottomed boat, without keel, and of small draught.

17. (n.) A straw hat, broad-brimmed and low-crowned.

18. (n.) A car without a roof, the body of which is a platform without sides; a platform car.

19. (n.) A platform on wheel, upon which emblematic designs, etc., are carried in processions.

20. (n.) The flat part, or side, of anything; as, the broad side of a blade, as distinguished from its edge.

21. (n.) A floor, loft, or story in a building; especially, a floor of a house, which forms a complete residence in itself.

22. (n.) A horizontal vein or ore deposit auxiliary to a main vein; also, any horizontal portion of a vein not elsewhere horizontal.

23. (n.) A dull fellow; a simpleton; a numskull.

24. (n.) A character [/] before a note, indicating a tone which is a half step or semitone lower.

25. (n.) A homaloid space or extension.

26. (v. t.) To make flat; to flatten; to level.

27. (v. t.) To render dull, insipid, or spiritless; to depress.

28. (v. t.) To depress in tone, as a musical note; especially, to lower in pitch by half a tone.

29. (v. i.) To become flat, or flattened; to sink or fall to an even surface.

30. (v. i.) To fall form the pitch.