flat

¹ American  

[flat] / flæt /

adjective

flatter, comparative flattest superlative

1. horizontally level.

   a flat roof.

   Synonyms:

   plane

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

3. having a surface that is without marked projections or depressions.

   a broad, flat face.

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

   He was flat on the canvas after the knockdown.

   Synonyms:

   prone, low

   Antonyms:

   vertical, upright

5. lying wholly on or against something.

   The banner was flat against the wall.

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

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

   a flat plate.

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

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

10. deflated; collapsed.

    a flat tire.

11. absolute, downright, or positive; without qualification.

    a flat denial.

    Synonyms:

    categorical, peremptory, outright

12. without modification or variation.

    a flat rate.

13. Informal. lacking money; broke.

14. without vitality or animation; lifeless; dull.

    flat writing.

    Synonyms:

    prosaic, spiritless, boring

    Antonyms:

    spirited

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

16. (of a beverage) having lost its effervescence.

17. without flavor; not spiced.

    flat cooking.

    Synonyms:

    unsavory, vapid

    Antonyms:

    savory, flavorful

18. prosaic, banal, or insipid.

    a flat style.

19. pointless, as a remark or joke.

20. commercially inactive.

    a flat day in the stock market.

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

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

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

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

25. lacking resonance and variation in pitch; monotonous.

    a flat delivery of the speech.

26. Music.

    1. (of a tone) lowered a half step in pitch.

       B flat.

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

27. 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.

28. Phonetics. lenis; voiced.

29. Nautical. (of a sail)

    1. cut with little or no fullness.

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

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

---

noun

1. something flat.

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

3. a flat surface, side, or part of anything.

   He struck me with the flat of his hand.

4. flat or level ground; a flat area.

   salt flats.

5. a marsh, shoal, or shallow.

6. Music.

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

   2. a tone one chromatic half step below another.

      The flat of B is B flat.

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

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

8. a broad, thin book, chiefly for children.

   a juvenile flat.

9. Informal. a deflated automobile tire.

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

11. Architecture. a flat roof or deck.

12. Nautical.

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

    2. a low, flat barge or lighter.

13. Shipbuilding.

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

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

14. an iron or steel bar of rectangular cross section.

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

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

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

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

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

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

21. Informal. flats, flat races between horses.

verb (used with object)

flatted, flatting

1. to make flat.

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

verb (used without object)

flatted, flatting

1. to become flat.

adverb

1. in a flat position; horizontally; levelly.

2. in a flat manner; positively; absolutely.

3. completely; utterly.

   flat broke.

4. exactly; precisely.

   She ran around the track in two minutes flat.

5. Music. below the true pitch.

   to sing flat.

6. Finance. without interest.

verb phrase

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

idioms

1. fall flat, to fail to produce the desired effect; fail completely.

   His attempts at humor fell flat.

2. flat aft, trimmed so that fore-and-aft sails present as flat a surface as possible, as in sailing close to the wind.

3. flat out,

   1. without hesitation; directly or openly.

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

   2. at full speed or with maximum effort.

4. flat on one's back. back.

flat ² American  

[flat] / flæt /

noun

Chiefly British.

1. an apartment or suite of rooms on one floor forming a residence.

---

flat ¹ British  

/ flæt /

adjective

1. horizontal; level

   flat ground

   a flat roof

2. even or smooth, without projections or depressions

   a flat surface

3. lying stretched out at full length; prostrate

   he lay flat on the ground

4. having little depth or thickness; shallow

   a flat dish

5. having a surface or side in complete contact with another surface

   flat against the wall

6. spread out, unrolled, or levelled

7. (of a tyre) deflated, either partially or completely

8. (of shoes) having an unraised or only slightly raised heel

9. 1. (of races, racetracks, or racecourses) not having obstacles to be jumped

   2. of, relating to, or connected with flat racing as opposed to steeplechasing and hurdling

      flat jockeys earn more

10. without qualification; total

    a flat denial

11. without possibility of change; fixed

    a flat rate

12. (prenominal or immediately postpositive) neither more nor less; exact

    he did the journey in thirty minutes flat

    a flat thirty minutes

13. unexciting or lacking point or interest

    a flat joke

14. without variation or resonance; monotonous

    a flat voice

15. (of food) stale or tasteless

16. (of beer, sparkling wines, etc) having lost effervescence, as by exposure to air

17. (of trade, business, a market, etc) commercially inactive; sluggish

18. (of a battery) fully discharged; dead

19. (of a print, photograph, or painting) lacking contrast or shading between tones

20. (of paint) without gloss or lustre; matt

21. (of a painting) lacking perspective

22. (of lighting) diffuse

23. music

    1. (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

    2. (of an instrument, voice, etc) out of tune by being too low in pitch Compare sharp

24. phonetics another word for lenis

25. 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

1. in or into a prostrate, level, or flat state or position

   he held his hand out flat

2. completely or utterly; absolutely

   he went flat against the rules

3. exactly; precisely

   in three minutes flat

4. music

   1. lower than a standard pitch

   2. too low in pitch Compare sharp

      she sings flat

5. to fail to achieve a desired effect, etc

6. informal

   1. with the maximum speed or effort

   2. totally exhausted

noun

1. a flat object, surface, or part

2. (often plural) a low-lying tract of land, esp a marsh or swamp

3. (often plural) a mud bank exposed at low tide

4. music

   1. an accidental that lowers the pitch of the following note by one chromatic semitone

   2. a note affected by this accidental Compare sharp

5. theatre a rectangular wooden frame covered with painted canvas, etc, used to form part of a stage setting

6. a punctured car tyre

7. ((often cap.))

   1. flat racing, esp as opposed to steeplechasing and hurdling

   2. the season of flat racing

8. nautical a flatboat or lighter

9. a shallow box or container, used for holding plants, growing seedlings, etc

verb

1. to make or become flat

2. music the usual US word for flatten

flat ² British  

/ flæt /

noun

1. Usual US and Canadian name: apartment.  a set of rooms comprising a residence entirely on one floor of a building

2. a portion of a house used as separate living quarters

3. a house shared with people who are not members of one's own family

---

verb

1. to live in a flat (with someone)

flat More Idioms  

More idioms and phrases containing flat

• caught flat-footed
• fall flat
• in no time (nothing flat)
• leave flat

---

Synonym Usage

See level.

Other Word Forms

Derived Forms

• flatness
  noun
• unflatted
  adjective
• flatly
  adverb

Inflected Forms

Adjectives

• flatter
  comparative
• flattest
  superlative

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.

Example Sentences

See Examples For:

flat flatter flattest flatted flatting

A sprint finish was expected on Wednesday, a flat 161.3km route from Vichy to Nevers, and Cees Bol made the first move as the peloton rolled into the final 500m after catching the day's breakaway.

From BBC ● Jul. 15, 2026

—U.S. futures were mostly in the green, with the S&P 500 up 0.2% and Nasdaq futures climbing 0.9%, though futures for the Dow Jones Industrial Average were flat.

From The Wall Street Journal ● Jul. 15, 2026

Unlike trees, mountains, rivers, clouds, and animals, which are dominated by curved and branching forms, crystals stand out because of their flat surfaces and straight edges.

From Science Daily ● Jul. 15, 2026

He quickly walked his children back to their flat but returned to the park to collect his car.

From BBC ● Jul. 15, 2026

He followed the ridge until he came close to the stretch of flat ice and the breathing hole where the seal had shown its head.

From "Black Star, Bright Dawn" by Scott O'Dell

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

Former world number one Medvedev generally hits flatter with his groundstrokes, meaning the ball stays lower on the clay and allows his opponents to return more comfortably.

From BBC ● May 26, 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

Mr. Shear, who also wrote and directed the movie, a feature debut, doesn’t flatter himself as an actor.

From The Wall Street Journal ● Mar. 26, 2026

Those men only murmured sweet nonsense to me, trying in vain to flatter me.

From "Dreaming in Cuban" by Cristina García

So it proved after Pakistan won the toss in oppressive heat and pounced on the chance to bat first on the flattest of pitches.

From BBC ● Oct. 7, 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

They marched north, skirting the edge of the city, and headed to the Field of Mars—the largest, flattest part of the valley.

From "The Son of Neptune" by Rick Riordan

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

One Kreinik resident said a camp of displaced persons had been flatted and thousands of people had sought refuge in government buildings.

From Reuters ● Dec. 9, 2021

Fly Away made a big move in her last start to take the lead but flatted out late to finish third.

From Seattle Times ● Jun. 29, 2013

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

She turned her back I went around in front of her the rain creeping into the mud flatting her bodice through her dress it smelled horrible.

From "The Sound and the Fury" by William Faulkner

Related Words

• bland
• dead
• lifeless
• stale
• weak