The Collaborative International Dictionary of English v.0.48:

Calcaneum \Cal*ca"ne*um\n.; pl. E. -neums, L. -nea. [L. the
   heel, fr. calx, calcis, the heel.] (Anal.)
   One of the bones of the tarsus which in man, forms the great
   bone of the heel; -- called also fibulare.
   [1913 Webster]