\Cal"cu*lus\, n.; pl. {Calculi}. [L, calculus. See
{Calculate}, and {Calcule}.]
1. (Med.) 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.
2. (Math.) A method of computation; any process of reasoning
   by the use of symbols; any branch of mathematics that may
   involve calculation.
{Barycentric calculus}, a method of treating geometry by
   defining a point as the center of gravity of certain other
   points to which co["e]fficients or weights are ascribed.
{Calculus of functions}, that branch of mathematics which
   treats of the forms of functions that shall satisfy given
   conditions.
{Calculus of operations}, that branch of mathematical logic
   that treats of all operations that satisfy given
   conditions.
{Calculus of probabilities}, the science that treats of the
   computation of the probabilities of events, or the
   application of numbers to chance.
{Calculus of variations}, a branch of mathematics in which
   the laws of dependence which bind the variable quantities
   together are themselves subject to change.
{Differential calculus}, a method of investigating
   mathematical questions by using the ratio of certain
   indefinitely small quantities called differentials. The
   problems are primarily of this form: to find how the
   change in some variable quantity alters at each instant
   the value of a quantity dependent upon it.
{Exponential calculus}, that part of algebra which treats of
   exponents.
{Imaginary calculus}, a method of investigating the relations
   of real or imaginary quantities by the use of the
   imaginary symbols and quantities of algebra.
{Integral calculus}, a method which in the reverse of the
   differential, the primary object of which is to learn from
   the known ratio of the indefinitely small changes of two
   or more magnitudes, the relation of the magnitudes
   themselves, or, in other words, from having the
   differential of an algebraic expression to find the
   expression itself.