natural number

noun

1. A positive integer {1, 2, 3, ...}.
2. A non-negative integer {0, 1, 2, ...}.

   “A careful derivation of the arithmetic properties of the natural numbers #92;mathbb#123;N#125;, using induction, was done by G. Peano (1858–1932). It is a lot of fun, but we will not pursue any of it here.”