ordinal number

From Wiktionary

Noun[change]

Singular
ordinal number

Plural
ordinal numbers

  1. (grammar) An ordinal number tells where in a sequence a thing is.
    First is the ordinal number corresponding to one.
    Tenth is an ordinal number that says there are nine things before this one.
    "You didn't get 'three prize,' Bill, you got third prize. Use the ordinal number."