Definition:Odd Integer/Odd-Times Odd/Definition 1

Definition

Let $n \in \Z$ be an integer.

$n$ is odd-times odd if and only if it is an odd number greater than $1$ which is not prime.

Euclid's Definition

In the words of Euclid:

An odd-times odd number is that which is measured by an odd number according to an odd number.

(The Elements: Book $\text{VII}$: Definition $10$)

Also see

• Equivalence of Definitions of Odd-Times Odd Integer