The Collaborative International Dictionary of English v.0.48:

Etch \Etch\, v. t. [imp. & p. p. Etched; p. pr. & vb. n.
   Etching.] [D. etsen, G. [aum]tzen to feed, corrode, etch.
   MHG. etzen, causative of ezzen to eat, G. essen ??. See
   Eat.]
   1. To produce, as figures or designs, on mental, glass, or
      the like, by means of lines or strokes eaten in or
      corroded by means of some strong acid.
      [1913 Webster]

   Note: The plate is first covered with varnish, or some other
         ground capable of resisting the acid, and this is then
         scored or scratched with a needle, or similar
         instrument, so as to form the drawing; the plate is
         then covered with acid, which corrodes the metal in the
         lines thus laid bare.
         [1913 Webster]

   2. To subject to etching; to draw upon and bite with acid, as
      a plate of metal.
      [1913 Webster]

            I was etching a plate at the beginning of 1875.
                                                  --Hamerton.
      [1913 Webster]

   3. To sketch; to delineate. [R.]
      [1913 Webster]

            There are many empty terms to be found in some
            learned writes, to which they had recourse to etch
            out their system.                     --Locke.
      [1913 Webster]

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.
      [1913 Webster]

   3. An impression on paper, parchment, or other material,
      taken in ink from an etched plate.
      [1913 Webster]

   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]

WordNet (r) 3.0 (2006):

etching
    n 1: an impression made from an etched plate
    2: an etched plate made with the use of acid
    3: making engraved or etched plates and printing designs from
       them [syn: engraving, etching]

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "etching":
   abstract art, aquatint, art, art form, artist, arts and crafts,
   arts of design, autolithograph, block, block print, burr,
   calligraphy, cave art, ceramics, cerography, chalcography,
   chiseling, chromolithograph, color print, copperplate,
   copperplate print, crayon engraving, cribbling, cross-hatching,
   cut, decoration, demitint, design, designing, drypoint,
   engravement, engraving, etch, fine arts, folk art, gem-engraving,
   glass-cutting, glyptic, graphic arts, graphotype, graving,
   half tint, hatching, impress, impression, imprint, incision,
   inscript, inscription, intaglio, line, lining,
   linoleum-block print, lithograph, marking, metal cut, mezzotint,
   negative, photoengraving, photography, plastic art,
   plate engraving, primitive art, print, pyrogravure, relief method,
   rubber-block print, score, scoring, scratch, scratching, sculpture,
   slash, slashing, steel engraving, stipple, stippling, the arts,
   tint, tooling, type-cutting, vignette, wood engraving, woodblock,
   woodburning, woodcut, woodprint, xylograph, zincography