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adj. flat·ter, flat·test
a. Having a smooth, even surface: a flat field. See Synonyms at level.
b. Having a relatively broad level surface in relation to thickness or depth: a flat box.
a. Being in horizontal position; lying down: flat on his back.
b. Being without slope or curvature: a flat line on a chart.
c. Having a low heel or no heel: flat shoes.
3. Free of qualification; absolute: a flat refusal.
4. Fixed; unvarying: a flat rate.
5. Lacking interest or excitement; dull: a flat scenario.
a. Lacking in flavor: a flat stew that needs salt.
b. Having lost effervescence or sparkle: flat beer.
a. Deflated. Used of a tire.
b. Electrically discharged. Used of a storage battery.
8. Of or relating to a horizontal line that displays no ups or downs and signifies the absence of physiological activity: A flat electroencephalogram indicates a loss of brain function.
9. Of or relating to a hierarchy with relatively few tiers or levels: a flat organization chart.
10. Commercially inactive; sluggish: flat sales for the month.
11. Unmodulated; monotonous: a flat voice.
12. Lacking variety in tint or shading; uniform: "The sky was bright but flat, the color of oyster shells" (Anne Tyler).
13. Not glossy; matte: flat paint.
a. Being below the correct pitch.
b. Being one half step lower than the corresponding natural key: the key of B flat.
15. Designating the vowel a as pronounced in bad or cat.
16. Nautical Taut. Used of a sail.
17. Informal Having small breasts.
a. Level with the ground; horizontally.
b. On or up against a flat surface; at full length.
2. So as to be flat.
a. Directly; completely: went flat against the rules; flat broke.
b. Exactly; precisely: arrived in six minutes flat.
4. Music Below the intended pitch.
5. Business Without interest charge.
1. A flat surface or part.
2. often flats A stretch of level ground: salt flats.
3. A shallow frame or box for seeds or seedlings.
4. A movable section of stage scenery, usually consisting of a wooden frame and a decorated panel of wood or cloth.
5. A flatcar.
6. A deflated tire.
7. A shoe with a flat heel.
8. A large flat piece of mail.
9. A horse that competes in a flat race. Also called runner.
a. A sign (♭) used to indicate that a note is to be lowered by a semitone.
b. A note that is lowered a semitone.
11. Football The area of the field to either side of an offensive formation.
v. flat·ted, flat·ting, flats
1. To make flat; flatten.
2. Music To lower (a note) a semitone.
To sing or play below the proper pitch.
1. An apartment on one floor of a building.
2. Archaic A story in a house.
[Alteration of Scots flet, inner part of a house, from Middle English, from Old English, floor, dwelling; see plat- in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Metallurgy) metallurgy the process of flattening metal into a sheet by rolling
2. NZ the practice of sharing a house with people who are not members of one's own family
NZ to leave the parental home and live independently in a flat, usually with people of the same age group
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014