calculus

n. (pl. -luses or -li) 1 particular method of mathematical calculation or reasoning. 2 stone or mineral mass in the body. [latin, = small stone (used on an abacus)]

n. Any solid concretion, formed in any part of the body, but most frequent in the organs that act as reservoirs, and in the passages connected with them; as, biliary calculi; urinary calculi, etc.