The Collaborative International Dictionary of English v.0.48:

Cuish \Cuish\ (kw?s), n. [F. cuisse thigh, fr. L. coxa hip: cf.
   F. cuissard, OF, cuissot, armor for the thigh, cuish. Cf.
   Hough.]
   Defensive armor for the thighs. [ Written also cuisse, and
   quish.]
   [1913 Webster]