calculus, concretion -- (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")
tartar, calculus, tophus -- (an incrustation that forms on the teeth and gums)
calculus, infinitesimal calculus -- (the branch of mathematics that is concerned with limits and with the differentiation and integration of functions)
(Sound)
