Source : Webster's Revised Unabridged Dictionary (1913)

Flat \Flat\, v. t. [imp. & p. p. {Flatted}; p. pr. & vb. n.
   {Flatting}.]
   1. To make flat; to flatten; to level.

   2. To render dull, insipid, or spiritless; to depress.

            Passions are allayed, appetites are flatted.
                                                  --Barrow.

   3. To depress in tone, as a musical note; especially, to
      lower in pitch by half a tone.

Flatting \Flat"ting\, n.
   1. The process or operation of making flat, as a cylinder of
      glass by opening it out.

   2. A mode of painting,in which the paint, being mixed with
      turpentine, leaves the work without gloss. --Gwilt.

   3. A method of preserving gilding unburnished, by touching
      with size. --Knolles.

   4. The process of forming metal into sheets by passing it
      between rolls.

   {Flatting coat}, a coat of paint so put on as to have no
      gloss.

   {Flatting furnace}. Same as {flattening oven}, under
      {Flatten}.

   {Flatting mill}.
      (a) A rolling mill producing sheet metal; esp., in mints,
          the ribbon from which the planchets are punched.
      (b) A mill in which grains of metal are flatted by steel
          rolls, and reduced to metallic dust, used for purposes
          of ornamentation.

Source : WordNet®

flat
     adj 1: having a horizontal surface in which no part is higher or
            lower than another; "a flat desk"; "acres of level
            farmland"; "a plane surface" [syn: {level}, {plane}]
     2: having no depth or thickness
     3: not modified or restricted by reservations; "a categorical
        denial"; "a flat refusal" [syn: {categoric}, {categorical},
         {unconditional}]
     4: stretched out and lying at full length along the ground;
        "found himself lying flat on the floor" [syn: {prostrate}]
     5: lacking contrast or shading between tones [ant: {contrasty}]
     6: lowered in pitch by one chromatic semitone; "B flat" [ant: {natural},
         {sharp}]
     7: flattened laterally along the whole length (e.g., certain
        leafstalks or flatfishes) [syn: {compressed}]
     8: lacking taste or flavor or tang; "a bland diet"; "insipid
        hospital food"; "flavorless supermarket tomatoes"; "vapid
        beer"; "vapid tea" [syn: {bland}, {flavorless}, {flavourless},
         {insipid}, {savorless}, {savourless}, {vapid}]
     9: lacking stimulating characteristics; uninteresting; "a bland
        little drama"; "a flat joke" [syn: {bland}]
     10: having lost effervescence; "flat beer"; "a flat cola"
     11: not increasing as the amount taxed increases [syn: {fixed}]
     12: not made with leavening; "most flat breads are made from
         unleavened dough" [syn: {unraised}]
     13: parallel to the ground; "a flat roof"
     14: without pleats [syn: {unpleated}]
     15: lacking the expected range or depth; not designed to give an
         illusion or depth; "a film with two-dimensional
         characters"; "a flat two-dimensional painting" [syn: {two-dimensional}]
     16: (of a tire) completely or partially deflated
     17: not reflecting light; not glossy; "flat wall paint"; "a
         photograph with a matte finish" [syn: {mat}, {matt}, {matte},
          {matted}]
     18: lacking variety in shading; "a flat unshaded painting"
     [also: {flatting}, {flatted}, {flattest}, {flatter}]

flat
     adv 1: at full length; "he fell flat on his face"
     2: with flat sails; "sail flat against the wind"
     3: below the proper pitch; "she sang flat last night"
     4: against a flat surface; "he lay flat on his back"
     5: in a forthright manner; candidly or frankly; "he didn't
        answer directly"; "told me straight out"; "came out flat
        for less work and more pay" [syn: {directly}, {straight}]
        [ant: {indirectly}]
     6: wholly or completely; "He is flat broke"
     [also: {flatting}, {flatted}, {flattest}, {flatter}]

flat
     n 1: a level tract of land
     2: a shallow box in which seedlings are started
     3: a musical notation indicating one half step lower than the
        note named
     4: freight car without permanent sides or roof [syn: {flatcar},
         {flatbed}]
     5: a deflated pneumatic tire [syn: {flat tire}]
     6: scenery consisting of a wooden frame covered with painted
        canvas; part of a stage setting
     7: a suite of rooms usually on one floor of an apartment house
        [syn: {apartment}]
     [also: {flatting}, {flatted}, {flattest}, {flatter}]

flatting
     See {flat}