flat (adjective, noun) 

A flat tire 

په‌نچه‌ر - ته‌خت - پان 

Something that is flat is horizontally level.

• In the state of Nebraska, the land is very flat.
• Snow collected on the flat roof.
• They placed the map flat on the table to plan their trip.

In the UK, a flat is a residence within a building.

• Nevil shared his London flat with two friends.

Common uses

Ballet slippers or other dressy women’s shoes with low heels are called flats.

When a tire has a hole in it and the air goes out, it’s called a flat tire.

flat¹ /flæt/  

adj.,  flat•ter, flat•test, adv., n. 

adj. 

1. horizontally level:
   flat, white roofs on the houses of the Greek town.
2. level, even, or smooth in surface, such as land or tabletops:
   the flat prairie.
3. lying horizontally and at full length:
   flat on the floor.
4. not deep, high, or thick:
   stacks of flat boxes at the pizzeria.
5. spread out, as an unrolled map or the open hand:
   The map was flat on the table.
6. with the air out;
   deflated;
   collapsed:
   a flat tire.
7. absolute;
   downright;
   complete;
   definite:
   [before a noun]
   issued a flat denial of the charges.
8. without the possibility of change or variation;
   fixed:
   [before a noun]
   The hotel charged a flat rate.
9. lacking vitality or animation:
   a flat play.
10. (of a carbonated beverage) having lost its bubbles:
    The soda is flat.
11. pointless, as a remark or joke:
    a flat joke.
12. (of paint) without gloss;
    not shiny;
    matte.
13. lacking variation in pitch;
    monotonous:
    answered in a flat, bored voice.
14. Music and Dance
    • [after a letter indicating tone]
      (of a tone) lowered a half step in pitch:
      B flat.
    • below an intended pitch, such as a note;
      too low (opposed to sharp):
      The chorus was a little flat on that last song.

adv. 

15. in a flat position;
    horizontally;
    levelly:
    The trees had been laid flat by the hurricane.
16. completely;
    utterly:
    flat broke until payday.
17. exactly;
    precisely:
    [after a measurement of time]
    I got there in two minutes flat.
18. Music and Dance
    below the true pitch:
    to sing flat.

n. 

[countable]

19. Clothing
    a woman's shoe with a very low heel or no heel.
20. a flat surface, side, or part of anything:
    She held the stone in the flat of her hand.
21. flat or level ground:
    salt flats.
22. Music and Dance
    • (in musical notation) the character ♭
      , which indicates that the pitch of a note is lowered by one half step.
    • a tone that is one half step below another.
23. an automobile tire that has lost the air.

Idioms

24. Idioms
    fall flat, 
    [no object]
     to fail completely and noticeably:
    an attempt at humor that fell flat.
25. Idioms
    flat out, 
    [Informal.]
    • without hesitation;
      directly or openly:
      The spy told us flat out he had been a double agent.
    • at full speed or with maximum effort:
      We drove flat out to get there by afternoon.

flat•ly, adv. 

flat•ness, n. 

[uncountable]

flat² /flæt/  

n. 

[countable]

1. British Terms
   a residential apartment:
   rented a flat in the city.

-flat-, root. 

1. -flat- comes from Latin, where it has the meaning "blow;
   wind.'' This meaning is found in such words as: deflate, inflate.

WordReference Random House Unabridged Dictionary of American English © 2018

flat¹  (flat), 

adj.,  flat•ter, flat•test, n., v.,  flat•ted, flat•ting, adv. 

adj. 

1. horizontally level:
   a flat roof.
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.
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.
12. without modification or variation:
    a flat rate.
13. [Informal.]
    lacking money;
    broke.
14. without vitality or animation;
    lifeless;
    dull:
    flat writing.
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.
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.]
    • (of a tone) lowered a half step in pitch:
      B flat.
    • below an intended pitch, as a note;
      too low (opposed to sharp).
27. [Gram.]
    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. [Phonet.]
    lenis;
    voiced.
29. [Naut.]
    (of a sail)
    • cut with little or no fullness.
    • trimmed as nearly fore-and-aft as possible, for sailing to windward.
30. flat a, the a-sound (a) of glad, bat, or act.
31. flat aft, 
    [Naut.]
    trimmed so that fore-and-aft sails present as flat a surface as possible, as in sailing close to the wind.
32. flat on one's back. See  back (def. 19).

n. 

33. something flat.
34. a shoe, esp. a woman's shoe, with a flat heel or no heel.
35. a flat surface, side, or part of anything:
    He struck me with the flat of his hand.
36. flat or level ground;
    a flat area:
    salt flats.
37. a marsh, shoal, or shallow.
38. [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.
39. [Theat.]
    a piece of scenery consisting of a wooden frame, usually rectangular, covered with lightweight board or fabric.
40. a broad, thin book, chiefly for children:
    a juvenile flat.
41. [Informal.]
    a deflated automobile tire.
42. (in postal use) a large flat package, as in a manila envelope, for mailing.
43. [Archit.]
    a flat roof or deck.
44. [Naut.]
    • Also called  platform. a partial deck between two full decks.
    • a low, flat barge or lighter.
45. [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.
46. an iron or steel bar of rectangular cross section.
47. [Textiles.]
    one of a series of laths covered with card clothing, used in conjunction with the cylinder in carding.
48. [Photog.]
    one or more negatives or positives in position to be reproduced.
49. [Print.]
    a device for holding a negative or positive flat for reproduction by photoengraving.
50. [Hort.]
    a shallow, lidless box or tray used for rooting seeds and cuttings and for growing young plants.
51. a similar box used for shipping and selling fruits and vegetables.
52. [Football.]
    the area of the field immediately inside of or outside of an offensive end, close behind or at the line of scrimmage.
53. flats, 
    [Informal.]
    flat races between horses. Cf. flat race.

v.t. 

54. to make flat.
55. [Music.]
    to lower (a pitch), esp. one half step.

v.i. 

56. to become flat.
57. flat in, 
    [Naut.]
    to pull the clew of (a fore-and-aft sail) as nearly amidships as possible. Also,  flatten in. 

adv. 

58. in a flat position;
    horizontally;
    levelly.
59. in a flat manner;
    positively;
    absolutely.
60. completely;
    utterly:
    flat broke.
61. exactly;
    precisely:
    She ran around the track in two minutes flat.
62. [Music.]
    below the true pitch:
    to sing flat.
63. Stock Exchange[Finance.]
    without interest.
64. fall flat, to fail to produce the desired effect;
    fail completely:
    His attempts at humor fell flat.
65. 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.