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adjective \ˈflat\

Simple Definition of flat

  • : having a smooth, level, or even surface : not having curves or bumps

  • : having a wide, smooth surface and little thickness

  • of a shoe heel : very low and wide; also of a shoe : having a flat heel or no heel

Full Definition of flat


  1. 1 a :  lying at full length or spread out upon the ground :  prostrate b :  utterly ruined or destroyed c :  resting with a surface against something

  2. 2 a :  having a continuous horizontal surface b :  being or characterized by a horizontal line or tracing without peaks or depressions <a flat EEG>

  3. 3 :  having a relatively smooth or even surface

  4. 4 :  arranged or laid out so as to be level or even

  5. 5 a :  having the major surfaces essentially parallel and distinctly greater than the minor surfaces <a flat piece of wood> b of a shoe heel :  very low and broad

  6. 6 a :  clearly unmistakable <a flat denial> b (1) :  not varying :  fixed <a flat rate> (2) :  having no fraction either lacking or in excess :  exact <in a flat 10 seconds> (3) of a frequency response :  not varying significantly throughout its range

  7. 7 a :  lacking in animation, zest, or vigor :  dull b :  lacking flavor :  tasteless c :  lacking effervescence or sparkle <flat ginger ale> d :  commercially inactive; also :  characterized by no significant rise or decline from one period to another <sales were flat> e of a tire :  lacking air :  deflated f chiefly British of a battery :  dead 3c, discharged

  8. 8 a (1) of a tone :  lowered a half step in pitch (2) :  lower than the proper pitch b of the vowel a :  pronounced as in bad or bat

  9. 9 a :  having a low trajectory b of a tennis stroke :  made so as to give little or no spin to the ball

  10. 10 :  not having an inflectional ending <flat adverbs>

  11. 11 of a sail :  taut

  12. 12 a :  uniform in hue or shade b :  having little or no illusion of depth c of a photograph or negative :  lacking contrast d of lighting conditions :  lacking shadows or contours e :  free from gloss <a flat paint> f :  two-dimensional 3 <flat characters>

  13. 13 :  of, relating to, or used in competition on the flat <a flat horse>

  14. 14 of a universe :  having a mass such that expansion halts only after infinite time and collapse never occurs

flat·ly adverb
flat·ness noun
flat·tish play \ˈfla-tish\ adjective

Examples of flat

  1. the flat top of the table

  2. the flat landscape of the prairie

  3. Coins are usually round and flat.

  4. a flat piece of wood

Origin of flat

Middle English, from Old Norse flatr; akin to Old High German flaz flat, and probably to Greek platys broad — more at place

First Known Use: 14th century

Synonym Discussion of flat

level, flat, plane, even, smooth mean having a surface without bends, curves, or irregularities. level applies to a horizontal surface that lies on a line parallel with the horizon <the vast prairies are nearly level>. flat applies to a surface devoid of noticeable curvatures, prominences, or depressions <the work surface must be flat>. plane applies to any real or imaginary flat surface in which a straight line between any two points on it lies wholly within that surface <the plane sides of a crystal>. even applies to a surface that is noticeably flat or level or to a line that is observably straight <trim the hedge so it is even>. smooth applies especially to a polished surface free of irregularities <a smooth skating rink>.

insipid, vapid, flat, jejune, banal, inane mean devoid of qualities that make for spirit and character. insipid implies a lack of sufficient taste or savor to please or interest <an insipid romance with platitudes on every page>. vapid suggests a lack of liveliness, force, or spirit <an exciting story given a vapid treatment>. flat applies to things that have lost their sparkle or zest <although well-regarded in its day, the novel now seems flat>. jejune suggests a lack of rewarding or satisfying substance <a jejune and gassy speech>. banal stresses the complete absence of freshness, novelty, or immediacy <a banal tale of unrequited love>. inane implies a lack of any significant or convincing quality <an inane interpretation of the play>.




Simple Definition of flat

  • : a level area of land

  • : a flat part or surface

  • : a musical note that is one semitone lower than a specified note

Full Definition of flat

  1. 1 a :  a level surface of land —usually used in plural <sagebrush flats> <tidal flats> b :  a stretch of land without obstacles; especially :  a track or course for a flat race —usually used with the <has won twice on the flat>

  2. 2 :  a flat part or surface <the flat of one's hand>

  3. 3 a :  a musical note or tone one half step lower than a specified note or tone b :  a character ♭ on a line or space of the musical staff indicating a half step drop in pitch

  4. 4 :  something flat: as a :  a shallow container for shipping produce b :  a shallow box in which seedlings are started c :  a flat piece of theatrical scenery d :  a shoe or slipper having a flat heel or no heel

  5. 5 chiefly British :  an apartment on one floor

  6. 6 :  a deflated tire

  7. 7 :  the area to either side of an offensive football formation

Examples of flat

  1. the flat of your hand

  2. the flat of a sword

14th Century

First Known Use of flat

14th century




Simple Definition of flat

  • : on or against a flat surface

  • : in the position of someone or something that is lying spread out on the ground or another surface

  • : exactly or precisely

Full Definition of flat

  1. 1 :  in a flat manner :  directly, positively

  2. 2 :  in a complete manner :  absolutely <flat broke>

  3. 3 :  below the proper musical pitch

  4. 4 :  without interest charge; especially :  without allowance or charge for accrued interest <bonds sold flat>

Examples of flat

  1. Lay the map flat on the desk.

  2. He slipped and landed flat on his back.

  3. We asked for more time but they turned us down flat.


First Known Use of flat





Definition of flat


  1. transitive verb
  2. 1 :  flatten

  3. 2 :  to lower in pitch especially by a half step

  4. intransitive verb
  5. :  to sing or play below the true pitch

Circa 1604

First Known Use of flat

circa 1604

Medical Dictionary


adjective \ˈflat\

Medical Definition of flat


  1. 1:  being or characterized by a horizontal line or tracing without peaks or depressions <the EEG is ominously flat indicating that her brain function is gone—Don Gold>

  2. 2:  characterized by general impoverishment in the presence of emotion-evoking stimuli <flat affect often occurs in schizophrenia>

  3. flat·ness noun

Seen and Heard

What made you want to look up flat? Please tell us where you read or heard it (including the quote, if possible).


February 14, 2016

to hug and kiss another person

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