The Collaborative International Dictionary of English v.0.48:

Etching \Etch"ing\, n.
   1. The act, art, or practice of engraving by means of acid
      which eats away lines or surfaces left unprotected in
      metal, glass, or the like. See Etch, v. t.
      [1913 Webster]

   2. A design carried out by means of the above process; a
      pattern on metal, glass, etc., produced by etching.
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   3. An impression on paper, parchment, or other material,
      taken in ink from an etched plate.
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   Etching figures (Min.), markings produced on the face of a
      crystal by the action of an appropriate solvent. They have
      usually a definite form, and are important as revealing
      the molecular structure.

   Etching needle, a sharp-pointed steel instrument with which
      lines are drawn in the ground or varnish in etching.

   Etching stitch (Needlework), a stitch used outline
      embroidery.
      [1913 Webster]