human-scienceslinguisticsphoneticsWithout variation in level, quantity, value, tone etc.

Without variation in level, quantity, value, tone etc.

• The walls were painted a flat gray.

Lacking liveliness or action; depressed; uninteresting; dull and boring.

• The party was a bit flat.
• The market is flat today as most traders are on holiday.

authorshipbroadcastingcommunicationsLacking liveliness or action; depressed; uninteresting; dull and boring.

• The author added a chapter to flesh out the book's flatter characters.

entertainmentlifestylemusicLowered by one semitone.

entertainmentlifestylemusicOf a note or voice, lower in pitch than it should be.

• Your A string is flat.

Absolute; downright; peremptory.

• His claim was in flat contradiction to experimental results.
• I'm not going to the party and that's flat.

Deflated, especially because of a puncture.

With all or most of its carbon dioxide having come out of solution so that the drink no longer fizzes or contains any bubbles.

beveragesfoodlifestyleLacking acidity without being sweet.

Unable to emit power; dead.

artshobbiesjugglingWithout spin; spinless.

datedhuman-scienceslinguisticsphoneticsSonant; vocal, as distinguished from a sharp (non-sonant) consonant.

grammarhuman-scienceslinguisticsNot having an inflectional ending or sign, such as a noun used as an adjective, or an adjective as an adverb, without the addition of a formative suffix; or an infinitive without the sign "to".

• Many flat adverbs, as in 'run fast', 'buy cheap', etc. are from Old English.

golfhobbieslifestyleHaving a head at a very obtuse angle to the shaft.

agriculturebusinesshorticultureFlattening at the ends.

Exact.

• He finished the race in a flat four minutes.

Such that the tensor product preserves exact sequences. See Flat module on Wikipedia.Wikipedia.

algebramathematicssciencesSuch that its target, regarded as a module over its source, is flat (as above).

algebraic-geometrygeometrymathematicsSuch that the induced map on every stalk is flat (as a map of rings).

Having little froth and little milk.

obsoleteslangFoolish; simple-minded.

• We either burns the old brooms, or, if we can, we sells ’em for a ha’penny to some other boy, if he’s flat enough to buy ’em.

Flat out (at top speed).

• In the dry, the racing cars can take the corner flat.

A type of flat-soled running shoe without spikes.

A thin, broad brush used in oil and watercolour painting.

The most prominent flat part of something.

• The outboard bales in each tier should be placed on their edges so that their flats will be presented to the sweat battens. This precaution is necessary to lessen the damage in case of chafage. If the bales chafe or become wet on their flats, only one or two layers will be damaged.

The most prominent flat part of something.

The most prominent flat part of something.

A wide, shallow container or pallet.

• a flat of strawberries
• In mild areas, start sowing seeds in pots and flats for later transplanting.

A large mail piece measuring at least 8 1/2 by 11 inches, such as catalogs, magazines, and unfolded paper enclosed in large envelopes.

rail-transportrailwaystransportA railroad car without a roof, and whose body is a platform without sides; a platform car or flatcar.

• For example, when trailers containing new automobiles were first piggybacked two areas of potential damage became evident: (1) diesel locomotive exhaust left a film of oil on the new autos; and (2) auto windshields could be scarred or cracked by the metal-tipped "tell-tales" which warn men atop trains of oncoming bridges or tunnels. Accordingly, automobiles aboard piggyback flats are usually coupled into the train 15 or more cars behind the locomotive; and telltales have been raised.

rail-transportrailwaystransportA flat spot on the wheel of a rail vehicle.

• The tender roared along vibrating vigorously; braking had resulted in "flats" on most of its tyres.

A flat-bottomed boat, without keel, and of small draught.

geometrymathematicssciencesA subset of n-dimensional space that is congruent to a Euclidean space of lower dimension.

A straw hat, broad-brimmed and low-crowned.

A flat sheet for use on a bed.

• You might think that Americans buy roughly the same number of fitted sheets as flats. Or, considering the market for electric blankets, duvets, and other covers, that consumers buy even more bottom sheets, simply forgoing the tops.

mediapublishingA flat, glossy children's book with few pages.

• This same publisher notes pricing is a crucial factor in the mass market field of $1, $1.95 and $2.95 "flats."

A platform on a wheel, upon which emblematic designs etc. are carried in processions.

businessminingA horizontal vein or ore deposit auxiliary to a main vein; also, any horizontal portion of a vein not elsewhere horizontal.

engineeringnatural-sciencesphysical-sciencesA rectangular wooden structure covered with masonite, lauan, or muslin, often produced in standard modules, that is used to build wall surfaces on stage. Flats can be painted and outfitted with doors and/or windows to depict a building or other part of a scene, and are a hard-surfaced alternative to a backcloth or backdrop.

biologyentomologynatural-sciencesAny of various hesperiid butterflies that spread their wings open when they land.

historicalAn early kind of toy soldier having a flat design.

• Among the many US museums hosting flats, we may mention the Toy Soldier Museum in the Pocono Mountains, supervised by the historian, collector and dealer J. Hillestad.

obsoleteA dull fellow; a simpleton.

• […] if you cannot make a speech, Because you are a flat, Go very quietly and drop A button in the hat!
• "He fancies he can play at billiards," said he. "I won two hundred of him at the Cocoa-Tree. HE play, the young flat! […]"

engineeringnatural-sciencesopticsA flat (i.e. plane) mirror

• "When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical"

slanggamblinggamesA cheater's die with the edges shaved to make certain rolls more likely.

• He would slip in his six-ace flats, shaved dice that were made to bring up sevens. He'd throw them just long enough to get well, and then replace them with legitimate cubes.

A 24-case of beer.