Definition of ordinal number in US English:

ordinal number


  • A number defining a thing's position in a series, such as “first,” “second,” or “third.” Ordinal numbers are used as adjectives, nouns, and pronouns.

    Compare with cardinal number
    • ‘His work on ordered sets and ordinal numbers is fundamental to the subject.’
    • ‘It basically revolves round the set of all ordinal numbers.’
    • ‘However, it was not to be, but the second paper describes his theory of well-ordered sets and ordinal numbers.’
    • ‘We should say immediately that the ancient Greeks had different systems for cardinal numbers and ordinal numbers so we must look carefully at what we mean by Greek number systems.’
    • ‘This pattern of language differences for ordinal numbers is reminiscent of findings for cardinal numbers in a number of ways.’


ordinal number

/ˈôrdnəl ˈnəmbər/