callus

In botany, a tissue that forms at a damaged plant surface. Composed of large, thin-walled parenchyma cells, it grows over and around the wound, eventually covering the exposed area.

In animals, a callus is a thickened pad of skin, formed where there is repeated rubbing against a hard surface. In humans, calluses often develop on the hands and feet of those involved in heavy manual work.

callus

Growth of healing tissue, also containing blood and bone-forming cells, that forms around the ends of a bone following a fracture. Callus formation is an important factor in the union of the fracture.