Pathology, Physiology .

a hardened or thickened part of the skin; a callosity.

a new growth of osseous matter at the ends of a fractured bone, serving to unite them.

Also, callose. Botany .

the tissue that forms over the wounds of plants, protecting the inner tissues and causing healing.

a deposit on the perforated area of a sieve tube.

(in grasses) a tough swelling at the base of a lemma or palea.

to form a callus.

to produce a callus or calluses on

Heavy work callused his hands.