Căl'lus, n.

n. [Lat. callus, callum. See CALLID.]

1. (Med.) (a.) Any preternatural hardness in the body, particularly of the skin, as on the hands or feet, from friction or pressure; the hardened edges of a wound or ulcer; callosity. (b.) The new growth of osseous matter between the extremities of fractured bones, serving to unite them. Dunglison.
2. (Hort.) The new formation over the end of a cutting, before it puts out rootlets.