Main Entry: ¹cal·lus

Pronunciation: \ˈka-ləs\

Function: noun

Etymology: Latin

Date: 1563

1 : a thickening of or a hard thickened area on skin or bark
2 : a mass of exudate and connective tissue that forms around a break in a bone and is converted into bone in healing
3 : soft tissue that forms over a wounded or cut plant surface