The Collaborative International Dictionary of English v.0.48:

Grisette \Gri*sette"\, n. [F., fr. grisette a gray woolen cloth,
   fr. gris gray. Grisettes were so called because they wore
   gray gowns made of this stuff. See Gars.]
   A French girl or young married woman of the lower class; more
   frequently, a young working woman who is fond of gallantry.
   --Sterne.
   [1913 Webster]