Flat a. [Compar. Flatter superl. Flattest ]
 1. Having an even and horizontal surface, or nearly so, without prominences or depressions; level without inclination; plane.
 Though sun and moon
 Were in the flat sea sunk.   --Milton.
 2. Lying at full length, or spread out, upon the ground; level with the ground or earth; prostrate; as, to lie flat on the ground; hence, fallen; laid low; ruined; destroyed.
    What ruins kingdoms, and lays cities flat!   --Milton.
    I feel . . . my hopes all flat.   --Milton.
 3. Fine Arts Wanting relief; destitute of variety; without points of prominence and striking interest.
    A large part of the work is, to me, very flat.   --Coleridge.
 4. Tasteless; stale; vapid; insipid; dead; as, fruit or drink flat to the taste.
 5. Unanimated; dull; uninteresting; without point or spirit; monotonous; as, a flat speech or composition.
 How weary, stale, flat, and unprofitable
 Seem to me all the uses of this world.   --Shak.
 6. Lacking liveliness of commercial exchange and dealings; depressed; dull; as, the market is flat.
 7. Clear; unmistakable; peremptory; absolute; positive; downright.
 Syn: -- flat-out.
    Flat burglary as ever was committed.   --Shak.
    A great tobacco taker too, -- that's flat.   --Marston.
 8. Mus. (a) Below the true pitch; hence, as applied to intervals, minor, or lower by a half step; as, a flat seventh; A flat. (b) Not sharp or shrill; not acute; as, a flat sound.
 9. Phonetics Sonant; vocal; -- applied to any one of the sonant or vocal consonants, as distinguished from a nonsonant (or sharp) consonant.
 10. Golf Having a head at a very obtuse angle to the shaft; -- said of a club.
 11.  Gram. Not having an inflectional ending or sign, 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, are from AS. adverbs in -ë, the loss of this ending having made them like the adjectives. Some having forms in ly, such as exceeding, wonderful, true, are now archaic.
 12.  Hort. Flattening at the ends; -- said of certain fruits.
 Flat arch. Arch. See under Arch, n., 2. (b).
 Flat cap, cap paper, not folded. See under Paper.
 Flat chasing, in fine art metal working, a mode of ornamenting silverware, etc., producing figures by dots and lines made with a punching tool. --Knight.
 Flat chisel, a sculptor's chisel for smoothing.
 Flat file, a file wider than its thickness, and of rectangular section. See File.
 Flat nail, a small, sharp-pointed, wrought nail, with a flat, thin head, larger than a tack. --Knight.
 Flat paper, paper which has not been folded.
 Flat rail, a railroad rail consisting of a simple flat bar spiked to a longitudinal sleeper.
 Flat rods Mining, horizontal or inclined connecting rods, for transmitting motion to pump rods at a distance. --Raymond.
 Flat rope, a rope made by plaiting instead of twisting; gasket; sennit.
 Note: Some flat hoisting ropes, as for mining shafts, are made by sewing together a number of ropes, making a wide, flat band. --Knight.
 Flat space. Geom. See Euclidian space.
 Flat stitch, the process of wood engraving. [Obs.]
 Flat tint Painting, a coat of water color of one uniform shade.
 To fall flat (Fig.), to produce no effect; to fail in the intended effect; as, his speech fell flat.
 Of all who fell by saber or by shot,
 Not one fell half so flat as Walter Scott.   --Lord Erskine.


 flat arch
      n : an arch with mutually supporting voussoirs that has a
          straight horizontal extrados and intrados [syn: {straight
          arch]