Definition from Wiktionary, the free dictionary
The word is used since the beginning of the 20th century in Mathematics. It has been built from the Latin verb denumerare meaning to count out.
denumerable (not comparable)
- (mathematics) Capable of being assigned numbers from the natural numbers. Especially applied to sets where finite sets and sets that have a one-to-one mapping to the natural numbers are called denumerable.
- The empty set is denumerable because it is finite; the rational numbers are, surprisingly, denumerable because every possible fraction can be assigned a number.