Definition:Semiprime Number

Definition
A semiprime (number) is an integer which is the product of two (not necessarily distinct) primes.

Examples
Obvious examples: if $p, p_1, p_2$ are prime, then:
 * $p^2$ is semiprime.
 * $2 p$ is semiprime.
 * $p_1 p_2$ is semiprime.

Also known as
A semiprime number is most usually referred to just as a semiprime.

The additional specifier number has been included in its name on so as to provive a convenient means of disambiguation from other objects whose names include the term semiprime.

Some sources refer to a semiprime as an almost-prime.

Some sources hyphenate: semi-prime.