callum | callus, i (noun N.m) : n. (, , m., Cels. 5, 18, 36; 5, 26, 31 al.; Domit. Mars. ap. Charis. p. 55; plur. calli, Scrib. Comp. 37; 205; Suet. Aug. 80) [cf. Gr. καλάμη; Lat. culmus, culmen].
* The hardened, thick skin upon animal bodies: fere res omnes aut corio sunt Aut etiam conchis aut callo aut cortice tectae,Lucr. 4, 935: calceamentum solorum callum,Cic. Tusc. 5, 32, 90: pedum,Plin. 22, 25, 60, § 127; cf. id. 9, 35, 54, § 108.—Plur., Suet. Aug. 80.—Hence
* Meton.
* Trop., hardness, callousness, insensibility, stupidity (rare; most freq. in Cic.): ipse labor quasi callum quoddam obducit dolori,renders callous to pain,Cic. Tusc. 2, 15, 36; 3, 22, 53; id. Fam. 9, 2, 3: ducere,Sen. Cons. ad Marc. 8, 2: inducere,Quint. 12, 6, 6.
* The hard skin or the hard flesh of plants: uvarum,Plin. 14, 1, 3, § 14: pirorum ac malorum,id. 15, 28, 34, § 116: fungorum,id. 22, 23, 47, § 96: foliorum,id. 16, 22, 34, § 82; Pall. Mart. 10, 28 al.
* The hard covering of the soil: terrae,Plin. 17, 5, 3, § 33; 19, 2, 11, § 33; 31, 4, 30, § 53; also, of the hardness of salt: salis,id. 16, 12, 23, § 56.

s. TLL