1. A set containing a certain number of objects selected from another set. The number of combinations of r objects chosen from a set of n is n C r = n! / ((n-r)! r!) where "n C r" is normally with n and r as subscripts or as n above r in parentheses. See also permutation. 2. In the theory of combinators, a combination denotes an expression in which function application is the only operation. (1995-04-10)
