Definition of: calculus

(kal′kyə·ləs) noun plural ·li (-lī) or ·lus·es
1. Pathol. A stonelike concretion, as in the bladder.
2. Math. A method of calculating by the use of a highly specialized system of algebraic symbols.
—differential calculus That branch of analysis which investigates the infinitesimal changes of constantly varying quantities when the relations between the quantities are given.
—integral calculus That branch of analysis which, from the relations among the infinitesimal changes or variations of quantities, deduces relations among the quantities themselves, as in finding the area enclosed by a given curve. [<L, a pebble (used in counting)]