callōsĭtas, ātis, f. [callosus],
hardness of skin , callousness (post-class.), Scrib. Comp. 36: fistulae, Veg. 3, 27, 3.—Trop., hardness , a hardening : usus communis, Tert. Testim. Anim. 8: voluntarii erroris, id. adv. Nat. 2, 1.