countable

Short definition from Wiktionary

Adjective

1. 1
   Capable of being counted; having a quantity.
2. 2
   Finite or countably infinite; having a one-to-one correspondence (bijection) with a subset of the natural numbers.
3. 3
   Finite or countably infinite; having a one-to-one correspondence (bijection) with a subset of the natural numbers: Countably infinite; having a bijection with the natural numbers.
4. 4
   Freely usable with the indefinite article and with numbers.

Noun

1. 1
   A noun that is countable.