Mathematics . a method of calculation, esp. one of several highly systematic methods of treating problems by a special system of algebraic notations, as differential or integral calculus.

Pathology . a stone, or concretion, formed in the gallbladder, kidneys, or other parts of the body.

Also called tartar. Dentistry . a hard, yellowish to brownish-black deposit on teeth formed largely through the mineralization of dead bacteria in dental plaques by the calcium salts in salivary secretions and subgingival transudates.

calculation; estimation or computation

the calculus of political appeal.