countable
A term describing a {set} which is {isomorphic}
to a subet of the {natural numbers}. A countable set has
"countably many" elements. If the isomorphism is stated
explicitly then the set is called "a counted set" or "an
{enumeration}".
Examples of countable sets are any {finite} set, the {natural
numbers}, {integers}, and {rational numbers}. The {real
numbers} and {complex numbers} are not [proof?].
(1999-08-29)