Callus
Callus (kal"lus) , noun
[L. See Callous.]
1.
(b)
(Medicine) 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.
2.
(Horticulture) The new formation over the end of a cutting, before it puts out rootlets.