The Collaborative International Dictionary of English v.0.48:

Callosity \Cal*los"i*ty\, n.; pl. Callosities. [L. callasitas;
   cf. F. calost['e].]
   A hard or thickened spot or protuberance; a hardening and
   thickening of the skin or bark of a part, eps. as a result of
   continued pressure or friction.
   [1913 Webster]

WordNet (r) 3.0 (2006):

callosity
    n 1: an area of skin that is thick or hard from continual
         pressure or friction (as the sole of the foot) [syn:
         callosity, callus]
    2: devoid of passion or feeling; hardheartedness [syn:
       unfeelingness, callousness, callosity, hardness,
       insensibility]