Noun

1. A number used to denote quantity; a counting number.

   The smallest cardinal numbers are 0, 1, 2, and 3.

   The cardinal number "three" can be represented as "3" or "three".

2. A generalized kind of number used to denote the size of a set, including infinite sets.

1. A word that expresses a countable quantity; a cardinal numeral.

   "Three" is a cardinal number, while "third" is an ordinal number.

Usage notes

• Cardinal numbers are generally construed as nouns but function as adjectives. When functioning as adjectives, a cardinal number may only precede a countable noun, and the noun will be plural, except for one, 1, minus one, or -1:

  zero dogs

  one cat

  one hundred one dalmatians

  minus one degree

  minus five meters

• Cardinal numbers may be used as ordinal numbers when preceded by a singular countable noun, especially if preceded by the word number :

  Dog five was injured.

  Seal off number two bulkhead.

• zero can serve as quantifier indicating none:

• It has zero fat.

• Cardinal numbers can serve as a rating scale. The most common examples range from 0 or 1 to 10 or 100. In the 1-to-10 example, 0 and numbers bigger than 10 are used for hyperbole.

  Bo was once considered a 10.

  The pain is 1.

  I didn't like the lyrics, but it's kinda danceable: I give it a 75.