From 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]
From 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]