flat
1 Americanadjective
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horizontally level.
a flat roof.
- Synonyms:
- plane
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level, even, or without unevenness of surface, as land or tabletops.
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having a surface that is without marked projections or depressions.
a broad, flat face.
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lying horizontally and at full length, as a person; prostrate.
He was flat on the canvas after the knockdown.
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lying wholly on or against something.
The banner was flat against the wall.
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thrown down, laid low, or level with the ground, as fallen trees or buildings.
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having a generally level shape or appearance; not deep or thick.
a flat plate.
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(of the heel of a shoe) low and broad.
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spread out, as an unrolled map or the open hand.
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deflated; collapsed.
a flat tire.
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absolute, downright, or positive; without qualification.
a flat denial.
- Synonyms:
- categorical, peremptory, outright
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without modification or variation.
a flat rate.
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Informal. lacking money; broke.
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without vitality or animation; lifeless; dull.
flat writing.
- Synonyms:
- prosaic, spiritless, boring
- Antonyms:
- spirited
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having lost its flavor, sharpness, or life, as wine or food; stale.
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(of a beverage) having lost its effervescence.
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without flavor; not spiced.
flat cooking.
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prosaic, banal, or insipid.
a flat style.
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pointless, as a remark or joke.
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commercially inactive.
a flat day in the stock market.
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(of a painting) not having the illusion of volume or depth.
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(of a photograph or painting) lacking contrast or gradations of tone or color.
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(of paint) without gloss; not shiny; mat.
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not clear, sharp, or ringing, as sound or a voice.
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lacking resonance and variation in pitch; monotonous.
a flat delivery of the speech.
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Music.
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(of a tone) lowered a half step in pitch.
B flat.
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below an intended pitch, as a note; too low (opposed to sharp).
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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.
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Phonetics. lenis; voiced.
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Nautical. (of a sail)
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cut with little or no fullness.
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trimmed as nearly fore-and-aft as possible, for sailing to windward.
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flat a, the a -sound (a) of glad, bat, or act.
noun
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something flat.
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a shoe, especially a woman's shoe, with a flat heel or no heel.
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a flat surface, side, or part of anything.
He struck me with the flat of his hand.
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flat or level ground; a flat area.
salt flats.
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a marsh, shoal, or shallow.
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Music.
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(in musical notation) the character ♭, which when attached to a note or to a staff degree lowers its significance one chromatic half step.
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a tone one chromatic half step below another.
The flat of B is B flat.
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(on keyboard instruments, with reference to any given note) the key next below or to the left.
-
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Theater. a piece of scenery consisting of a wooden frame, usually rectangular, covered with lightweight board or fabric.
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a broad, thin book, chiefly for children.
a juvenile flat.
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Informal. a deflated automobile tire.
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(in postal use) a large flat package, as in a manila envelope, for mailing.
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Architecture. a flat roof or deck.
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Nautical.
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Also called platform. a partial deck between two full decks.
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a low, flat barge or lighter.
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Shipbuilding.
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a broad, flat piece of iron or steel for overlapping and joining two plates at their edges.
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a straight timber in a frame or other assembly of generally curved timbers.
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an iron or steel bar of rectangular cross section.
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Textiles. one of a series of laths covered with card clothing, used in conjunction with the cylinder in carding.
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Photography. one or more negatives or positives in position to be reproduced.
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Printing. a device for holding a negative or positive flat for reproduction by photoengraving.
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Horticulture. a shallow, lidless box or tray used for rooting seeds and cuttings and for growing young plants.
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a similar box used for shipping and selling fruits and vegetables.
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Football. the area of the field immediately inside of or outside of an offensive end, close behind or at the line of scrimmage.
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Informal. flats, flat races between horses.
verb (used with object)
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to make flat.
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Music. to lower (a pitch), especially one half step.
verb (used without object)
adverb
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in a flat position; horizontally; levelly.
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in a flat manner; positively; absolutely.
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completely; utterly.
flat broke.
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exactly; precisely.
She ran around the track in two minutes flat.
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Music. below the true pitch.
to sing flat.
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Finance. without interest.
verb phrase
idioms
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fall flat, to fail to produce the desired effect; fail completely.
His attempts at humor fell flat.
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flat aft, trimmed so that fore-and-aft sails present as flat a surface as possible, as in sailing close to the wind.
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flat out,
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without hesitation; directly or openly.
He told us flat out he'd been a double agent.
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at full speed or with maximum effort.
-
-
flat on one's back. back.
noun
adjective
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horizontal; level
flat ground
a flat roof
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even or smooth, without projections or depressions
a flat surface
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lying stretched out at full length; prostrate
he lay flat on the ground
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having little depth or thickness; shallow
a flat dish
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having a surface or side in complete contact with another surface
flat against the wall
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spread out, unrolled, or levelled
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(of a tyre) deflated, either partially or completely
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(of shoes) having an unraised or only slightly raised heel
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(of races, racetracks, or racecourses) not having obstacles to be jumped
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of, relating to, or connected with flat racing as opposed to steeplechasing and hurdling
flat jockeys earn more
-
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without qualification; total
a flat denial
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without possibility of change; fixed
a flat rate
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(prenominal or immediately postpositive) neither more nor less; exact
he did the journey in thirty minutes flat
a flat thirty minutes
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unexciting or lacking point or interest
a flat joke
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without variation or resonance; monotonous
a flat voice
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(of food) stale or tasteless
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(of beer, sparkling wines, etc) having lost effervescence, as by exposure to air
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(of trade, business, a market, etc) commercially inactive; sluggish
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(of a battery) fully discharged; dead
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(of a print, photograph, or painting) lacking contrast or shading between tones
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(of paint) without gloss or lustre; matt
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(of a painting) lacking perspective
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(of lighting) diffuse
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music
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(immediately postpositive) denoting a note of a given letter name (or the sound it represents) that has been lowered in pitch by one chromatic semitone
B flat
-
(of an instrument, voice, etc) out of tune by being too low in pitch Compare sharp
-
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phonetics another word for lenis
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phonetics the vowel sound of a as in the usual US or S Brit pronunciation of hand, cat , usually represented by the symbol (æ)
adverb
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in or into a prostrate, level, or flat state or position
he held his hand out flat
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completely or utterly; absolutely
he went flat against the rules
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exactly; precisely
in three minutes flat
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music
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lower than a standard pitch
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too low in pitch Compare sharp
she sings flat
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to fail to achieve a desired effect, etc
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informal
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with the maximum speed or effort
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totally exhausted
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noun
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a flat object, surface, or part
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(often plural) a low-lying tract of land, esp a marsh or swamp
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(often plural) a mud bank exposed at low tide
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music
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an accidental that lowers the pitch of the following note by one chromatic semitone
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a note affected by this accidental Compare sharp
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theatre a rectangular wooden frame covered with painted canvas, etc, used to form part of a stage setting
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a punctured car tyre
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((often cap.))
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flat racing, esp as opposed to steeplechasing and hurdling
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the season of flat racing
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nautical a flatboat or lighter
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a shallow box or container, used for holding plants, growing seedlings, etc
verb
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to make or become flat
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music the usual US word for flatten
noun
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Usual US and Canadian name: apartment. a set of rooms comprising a residence entirely on one floor of a building
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a portion of a house used as separate living quarters
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a house shared with people who are not members of one's own family
verb
Synonym Usage
See level.
Other Word Forms
Derived Forms
Inflected Forms
Adjectives
Etymology
Origin of flat1
First recorded in 1275–1325; Middle English, from Old Norse flatr; akin to Old English flet “the ground, a floor of a house,” Greek platýs “wide, broad”; see also flat 2; plate
Origin of flat2
First recorded in 1795–1805; variant of obsolete flet, from Old English; see origin at flat 1
Explanation
A flat is an apartment. It's called a flat because all the rooms in it are usually on the same floor. The word flat is much more common in British than American English. Geometrically, something flat is an even, level plane, like Kansas relative to the Rocky Mountains, or the cargo area of a flatbed truck. As an adjective, flat means "less than lively." A flat soda has no bubbles. If your speech falls flat, no one was excited. If you get mugged you might choose to lie flat on the ground. A flat note is just below the right pitch. And if your cooking is flat, it's boring.
Vocabulary lists containing flat
Music - Introductory
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Music - Middle School
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Music - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Since 2011, incidence of most food-borne illness has remained flat.
From The Wall Street Journal ● Jul. 22, 2026
Gosling said the flat hand gesture has haunted him since it first appeared on the poster and physical media covers.
From Los Angeles Times ● Jul. 22, 2026
That included a 3.4% drop in North America deliveries — U.S.-only deliveries were down 4.3% — and declines in every region except South America, which was flat.
From MarketWatch ● Jul. 21, 2026
The Metropolitan Police has opened a corporate manslaughter investigation after a man died following a fall from the balcony of his flat in central London.
From BBC ● Jul. 21, 2026
Sam tried to tell Skipper's mom how to change a flat tire, but she didn't seem to want to listen.
From "All About Sam" by Lois Lowry
New ventures built with AI from the start offer a vision of how work might look elsewhere in the corporate world one day: a flatter structure with fewer co-workers where everyone is a player-coach.
From The Wall Street Journal ● Jul. 22, 2026
But when Jurado sarcastically introduced the next speaker — “Your favorite, Lineage, will now present!” — the joke fell flatter than a solar panel.
From Los Angeles Times ● Jul. 10, 2026
In the fifth over, Sooryavanshi looked primed to attack the off-spin of Will Jacks, only to run past a flatter one and be stumped.
From BBC ● Jul. 4, 2026
You will see, especially among younger people, more entrepreneurs launching smaller businesses or flatter structures as a result of these tools.
From Barron's ● Mar. 27, 2026
King Cai had told him to play the diplomat; to flatter the Queen yet promise nothing.
From "Huntress" by Malinda Lo
Brook and Root were helped by one of the flattest pitches on record in Multan.
From BBC ● Oct. 10, 2024
So instead, I've just defaulted to the flattest toppings vehicle I know — the tortilla.
From Salon ● Aug. 31, 2023
With the help of his wife, he printed the fish from a bottom-angled perspective to highlight the cut belly, which is more complex than the traditional technique of printing the flattest side of the fish.
From Los Angeles Times ● Jul. 31, 2023
“My first thought was to get some good hiking shoes, I guess because I thought I was going to Switzerland. And then I showed up in literally the flattest place I ever lived.”
From New York Times ● Jun. 19, 2023
Reaching from the cliff face to the far horizon is the bluest, flattest, sweetest sight I’ve ever seen.
From "Without Refuge" by Jane Mitchell
Caltrans officials are recommending that this section of roadway be flatted out to some extent, Mihranian said.
From Los Angeles Times ● Mar. 22, 2024
A sign outside a Methodist Church near Mayfield captured the powerlessness many here felt in surveying what just a few days ago were busy towns, now flatted and twisted beyond easy identification.
From Washington Post ● Dec. 12, 2021
Halsey’s fourth album, “If I Can’t Have Love, I Want Power,” announces its character from its first sounds: slowly tolling piano arpeggios with a few notes flatted into dissonance.
From New York Times ● Aug. 26, 2021
Over the past fortnight, anyone brave enough to stand in Raonic's firing line has been flatted by a series of 140 mph missiles.
From Reuters ● Jul. 9, 2016
So any scale with a flatted third and seventh can be called a Dorian scale.
From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones
“We’re talking today about flatting the curve,” Monaco said.
From Washington Post ● Apr. 16, 2020
Uneven spray patterns give you an uneven distribution of the flatting agent, which shows up as a very subtle variation in the sheen and doesn’t look good on a large table.
From New York Times ● Mar. 29, 2012
Last week, his 358th week in the presidency, he ran through the part of just plain Harry without missing a cue or flatting a tone.
From Time Magazine Archive
Volunteer smalltown choirs, unopposed by professionals, are still enthusiastically flatting their way through the complicated, sentimental standbys.
From Time Magazine Archive
All the same, though, wherever I happen to be, I don’t think I’m the type that doesn’t even lift a finger to prevent a wedding from flatting.
From "Nine Stories" by J. D. Salinger
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.