Source : Webster's Revised Unabridged Dictionary (1913)

Washerwoman \Wash"er*wom`an\, n.; pl. {Washerwomen}.
   1. A woman who washes clothes, especially for hire, or for
      others.

   2. (Zo["o]l.) The pied wagtail; -- so called in allusion to
      its beating the water with its tail while tripping along
      the leaves of water plants. [Prov. Eng.]