Definition of: flat

(flat) adjective flat·ter, flat·test
1. Having a surface that is a horizontal plane, or nearly so; level; without unevenness or inclination.
2. Without prominences or depressions; not curved or round or uneven: a flat country.
3. Lying prone upon the ground; prostrate; hence, overthrown; ruined.
4. Not qualified or softened in any way; positive; absolute: a flat refusal.
5. Deficient in distinctness, form, or interesting qualities; monotonous; stupid; tasteless; dull; insipid: a flat sermon, a flat market, flat wine.
6. Music Below pitch; minor or diminished: a flat third; having flats in the signature: a flat key.
7. Phonet. a Designating the vowel sound in man, as opposed to the sound in calm. b Of consonants, voiced: opposed to sharp.
8. Without gloss, as a painted surface.
9. Uniform in tint.
10. Lacking in contrast; without distinguishing light and shadow: an effect often aimed at in mural–painting.
11. Of a golf club, having the head set at a very obtuse angle to the shaft.
12. Gram. Having no inflectional or distinguishing ending or mark, as an adverb not ending in –ly, or a noun used as an adjective without the addition of a characterizing suffix, as in such expressions as to breathe deep, the sister arts, etc.
13. Not varying with changing conditions; uniform: a flat rate.
14. Wanting in tonal quality: said of a sound or accent.
—adverb
1. In a level state or position; so as to be flat; flatly.
2. Music Below the true pitch.
3. In finance, without interest.
4. Exactly; precisely: used of amounts, distances, and the like: It weighed ten pounds flat.
—noun
1. A plane surface; a level.
2. Low meadowland over which the tide flows, never completely submerged by water: used for pasturage or planting.
3. Shoal: commonly in the plural.
4. Anything that is flat; the flat side of a thing.
5. Music A tone a half step lower than a tone from which it is named, represented by the character ♭.
6. A strip of high, level land.
7. An oblong wooden frame covered with canvas; a unit of a box–set of stage scenery.
8. A platform car.
9. A flat–bottomed boat, used for transporting heavy cargoes; a flatboat.
10. A deflated automobile tire.
11. A shallow, earth–filled tray for earlier seed germination to advance the flowering period.
—v. flat·ted, flat·ting v.t.
1. To make flat.
2. Music To lower (a tone) in playing or composing, especially by a semitone.
—v.i.
3. To become flat.
4. Music To sing or play below pitch. [ON flatr]
—flat′ly adverb
—flat′ness noun Synonyms (adj.): absolute, characterless, downright, dull, empty, even, horizontal, insipid, level, lifeless, mawkish, pointless, spiritless, stupid, tame, vapid. As a dead level is monotonous and uninteresting, we have a flat joke, a flat remark, for one that is dull, insipid, pointless. As what is perfectly level is without variation or relief, we have a flat refusal, in the sense of what is absolute. See HORIZONTAL, LEVEL, SMOOTH.♦ Flat is the first element in many self–explaining compound adjectives: flat–billed, flat–bottomed, flat–breasted, etc.

flat² (flat) noun
1. A set of rooms on one floor, for the occupancy of a family; apartment.
2. A house containing such flats. [Var. of obs. flet, a floor OE flet; infl. by FLAT¹]

flat·boat (flat′bōt′) noun
A large boat with a flat bottom much in use on rivers for freighting merchandise: also flat. Also flat′bot′tom (-bot′·əm).

flat–bot·tomed (flat′bot′əmd) adjective
Having the bottom flat: usually said of boats.

flat car
A railroad freight car, usually without sides or covering; a platform car. Also flat.

flat·fish (flat′fish′) noun plural ·fish or ·fish·es
Any of an order (Heterosomata) of fishes having a compressed body with unsymmetrical sides and with both eyes on one side, as the flounder, halibut, sole, etc.

flat·foot (flat′ft′) noun
1. Pathol. The deformed condition of a foot caused by a falling of the arch.
2. plural flat·feet Slang A policeman.

flat foot
A foot having a flat sole.

flat–foot·ed (flat′ft′id) adjective
1. Having flat feet.
2. Uncompromising; resolute; positive.
—flat′–foot′ed·ly adverb

Flat·head (flat′hed′) noun
1. One of the Salishan tribe of North American Indians.
2. One of the Chinook Indians.