Callus
WordNet
noun
(1) (botany) an isolated thickening of tissue, especially a stiff protuberance on the lip of an orchid
(2) Bony tissue formed during the healing of a fractured bone
(3) An area of skin that is thick or hard from continual pressure or friction (as the sole of the foot)
verb
(4) Form a callus or calluses
"His foot callused"
(5) Cause a callus to form on
"The long march had callused his feet"