The Collaborative International Dictionary of English v.0.48:

Blanch \Blanch\ (bl[.a]nch), v. t. [imp. & p. p. Blanched
   (bl[.a]ncht); p. pr. & vb. n. Blanching.] [OE. blanchen,
   blaunchen, F. blanchir, fr. blanc white. See Blank, a.]
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   1. To take the color out of, and make white; to bleach; as,
      to blanch linen; age has blanched his hair.
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   2. (Gardening) To bleach by excluding the light, as the
      stalks or leaves of plants, by earthing them up or tying
      them together.
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   3. (Confectionery & Cookery)
      (a) To make white by removing the skin of, as by scalding;
          as, to blanch almonds.
      (b) To whiten, as the surface of meat, by plunging into
          boiling water and afterwards into cold, so as to
          harden the surface and retain the juices.
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   4. To give a white luster to (silver, before stamping, in the
      process of coining.).
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   5. To cover (sheet iron) with a coating of tin.
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   6. Fig.: To whiten; to give a favorable appearance to; to
      whitewash; to palliate.
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            Blanch over the blackest and most absurd things.
                                                  --Tillotson.
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   Syn: To Blanch, Whiten.

   Usage: To whiten is the generic term, denoting, to render
          white; as, to whiten the walls of a room. Usually
          (though not of necessity) this is supposed to be done
          by placing some white coloring matter in or upon the
          surface of the object in question. To blanch is to
          whiten by the removal of coloring matter; as, to
          blanch linen. So the cheek is blanched by fear, i. e.,
          by the withdrawal of the blood, which leaves it white.
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