horizontally level

a flat roof.

level, even, or without unevenness of surface, as land or tabletops.

having a surface that is without marked projections or depressions

a broad, flat face.

lying horizontally and at full length, as a person; prostrate

He was flat on the canvas after the knockdown.

lying wholly on or against something

The banner was flat against the wall.

thrown down, laid low, or level with the ground, as fallen trees or buildings.

having a generally level shape or appearance; not deep or thick

a flat plate.

(of the heel of a shoe) low and broad.

spread out, as an unrolled map or the open hand.

deflated; collapsed

a flat tire.

absolute, downright, or positive; without qualification

a flat denial.

without modification or variation

a flat rate.

Informal . lacking money; broke.

without vitality or animation; lifeless; dull

flat writing.

having lost its flavor, sharpness, or life, as wine or food; stale.

(of a beverage) having lost its effervescence.

without flavor; not spiced

flat cooking.

prosaic, banal, or insipid

a flat style.

pointless, as a remark or joke.

commercially inactive

a flat day in the stock market.

(of a painting) not having the illusion of volume or depth.

(of a photograph or painting) lacking contrast or gradations of tone or color.

(of paint) without gloss; not shiny; mat.

not clear, sharp, or ringing, as sound or a voice.

lacking resonance and variation in pitch; monotonous

a flat delivery of the speech.

Music .

(of a tone) lowered a half step in pitch

B flat.

below an intended pitch, as a note; too low ( opposed to sharp ).

Grammar . derived without change in form, as English to brush from the noun brush and adverbs that do not add -ly to the adjective form as fast, cheap, and slow.

Phonetics . lenis; voiced.

Nautical . (of a sail)

cut with little or no fullness.

trimmed as nearly fore-and-aft as possible, for sailing to windward.

flat a, the a -sound (a) of glad, bat, or act.

something flat.

a shoe, esp. a woman's shoe, with a flat heel or no heel.

a flat surface, side, or part of anything

He struck me with the flat of his hand.

flat or level ground; a flat area

salt flats.

a marsh, shoal, or shallow.

Music .

(in musical notation) the character ?, which when attached to a note or to a staff degree lowers its significance one chromatic half step.

a tone one chromatic half step below another

The flat of B is B flat.

(on keyboard instruments, with reference to any given note) the key next below or to the left.

Theater . a piece of scenery consisting of a wooden frame, usually rectangular, covered with lightweight board or fabric.

a broad, thin book, chiefly for children

a juvenile flat.

Informal . a deflated automobile tire.

(in postal use) a large flat package, as in a manila envelope, for mailing.

Architecture . a flat roof or deck.

Nautical .

Also called platform. a partial deck between two full decks.

a low, flat barge or lighter.

Shipbuilding .

a broad, flat piece of iron or steel for overlapping and joining two plates at their edges.

a straight timber in a frame or other assembly of generally curved timbers.

an iron or steel bar of rectangular cross section.

Textiles . one of a series of laths covered with card clothing, used in conjunction with the cylinder in carding.

Photography . one or more negatives or positives in position to be reproduced.

Printing . a device for holding a negative or positive flat for reproduction by photoengraving.

Horticulture . a shallow, lidless box or tray used for rooting seeds and cuttings and for growing young plants.

a similar box used for shipping and selling fruits and vegetables.

Football . the area of the field immediately inside of or outside of an offensive end, close behind or at the line of scrimmage.

flats, Informal . flat races between horses. Compare flat race .

to make flat.

Music . to lower (a pitch), esp. one half step.

to become flat.

in a flat position; horizontally; levelly.

in a flat manner; positively; absolutely.

completely; utterly

flat broke.

exactly; precisely

She ran around the track in two minutes flat.

Music . below the true pitch

to sing flat.

Finance . without interest. ?

flat in, Nautical . to pull the clew of (a fore-and-aft sail) as nearly amidships as possible. Also, flatten in. ?

fall flat

to fail to produce the desired effect; fail completely

His attempts at humor fell flat.

flat aft, Nautical . trimmed so that fore-and-aft sails present as flat a surface as possible

as in sailing close to the wind.

flat on one's back. back ( def. 19 ) .

flat out

Informal .

without hesitation; directly or openly

He told us flat out he'd been a double agent.

at full speed or with maximum effort.

adverb

emphatically , flat , positively