calculus

英['kælkjʊləs] 美['kælkjələs]

1. a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body;

"renal calculi can be very painful"

2. an incrustation that forms on the teeth and gums

3. the branch of mathematics that is concerned with limits and with the differentiation and integration of functions