Source : Webster's Revised Unabridged Dictionary (1913)

Thigh \Thigh\ (th[imac]), n. [OE. thi, [thorn]ih, [thorn]eh, AS.
   [thorn]e['o]h; akin to OFries. thiach, D. dij, dije, OHG.
   dioh, thioh, Icel. [thorn]j[=o] thigh, rump, and probably to
   Lith. taukas fat of animals, tukti to become fat, Russ. tuke
   fat of animals. [root]56.]
   1. (Anat.) The proximal segment of the hind limb between the
      knee and the trunk. See {Femur}.

   2. (Zo["o]l.) The coxa, or femur, of an insect.

   {Thigh bone} (Anat.), the femur.