What is "etching stitch"

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.

2. A design carried out by means of the above process; a pattern on metal, glass, etc., produced by etching.

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

   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.