In·fin·i·tes·i·mal a. Infinitely or indefinitely small; less than any assignable quantity or value; very small.
Infinitesimal calculus, the different and the integral calculus, when developed according to the method used by Leibnitz, who regarded the increments given to variables as infinitesimal.
infinitesimal calculus
n : the branch of mathematics that is concerned with limits and
with the differentiation and integration of functions
[syn: calculus, the calculus]