The Collaborative International Dictionary of English v.0.48:

Hors d'oeuvre \Hors` d'[oe]uvre"\; pl. Hors d'[oe]uveres. [F.,
   lit., outside of work.]
   1. Something unusual or extraordinary. [R.]
      [Webster 1913 Suppl.]

   2. A dish served as a relish, usually at the beginning of a
      meal.
      [Webster 1913 Suppl.]