calculi

(noun) a hard lump produced by the concretion of mineral salts; found in hollow organs or ducts of the body. Synonyms: calculus, concretion. Example: "Renal calculi can be very painful."

(noun) an incrustation that forms on the teeth and gums. Synonyms: tartar, calculus, tophus.

(noun) the branch of mathematics that is concerned with limits and with the differentiation and integration of functions. Synonyms: calculus, infinitesimal calculus.