cal·ca·ne·us 
(kăl-kānē-əs) also cal·ca·ne·um (-nē-əm)
(kăl-kānē-əs) also cal·ca·ne·um (-nē-əm)n. pl. cal·ca·ne·i (-nē-ī′) also cal·ca·ne·a (-nē-ə)
The quadrangular bone at the back of the tarsus. Also called heel bone.
[Late Latin calcāneus, heel, from Latin calcāneum, from calx, calc-.]
cal·cane·al adj.