Definition:Even Integer

Definition
Let $n$ be an integer.

Then $n$ is even iff it has $2$ as a divisor.

The first few non-negative even numbers are:
 * $0, 2, 4, 6, 8, 10, \ldots$

Euclid's Definition


Euclid went further and distinguished between even numbers which are multiples of $4$ and those which are not:

Also see

 * Definition:Odd Integer