Callus

Part of speech: noun (n.)

1. Same as Callosity. (b

2. The material of repair in fractures of bone; a substance exuded at the site of fracture, which is at first soft or cartilaginous in consistence, but is ultimately converted into true bone and unites the fragments into a single piece.

3. The new formation over the end of a cutting, before it puts out rootlets.