In mathematics, the term even is used in several senses:

• an integer is called even if it is divisible by two; see even and odd numbers
• a function f defined on the real numbers is called even if f(x) = f(−x) for all x; see even and odd functions
• a permutation of a finite set is called even if it can be written as a composition of an even number of transpositions; see even and odd permutations