Calculus n. : Any solid concretion, formed in any part of the body, but most frequent in the organs that act as reservoirs, and in the passages connected with them; as, biliary calculi; urinary calculi, etc.

Calculus n. : A method of computation; any process of reasoning by the use of symbols; any branch of mathematics that may involve calculation.

Example:
Calculus................................?

Taxonomy
calculus, derivative, infinitesimals, Newton, mathematicians, Leibniz, slope, dx, differential calculus, integral calculus, sum, curve, interval, Newton and Leibniz, antiderivative, differentiation, mathematics, the calculus.

Defination from the web:
calculus. ... Calculus is the study of change, in the same way that geometry is the study of shape and algebra is the study of operations and their application ...