The Collaborative International Dictionary of English v.0.48:

Flat \Flat\, v. t. [imp. & p. p. Flatted; p. pr. & vb. n.
   Flatting.]
   1. To make flat; to flatten; to level.
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   2. To render dull, insipid, or spiritless; to depress.
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            Passions are allayed, appetites are flatted.
                                                  --Barrow.
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   3. To depress in tone, as a musical note; especially, to
      lower in pitch by half a tone.
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The Collaborative International Dictionary of English v.0.48:

Flatting \Flat"ting\, n.
   1. The process or operation of making flat, as a cylinder of
      glass by opening it out.
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   2. A mode of painting,in which the paint, being mixed with
      turpentine, leaves the work without gloss. --Gwilt.
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   3. A method of preserving gilding unburnished, by touching
      with size. --Knolles.
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   4. The process of forming metal into sheets by passing it
      between rolls.
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   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 mill producing 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.
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