English

Numeral

thirty-first

1. (ordinal) The ordinal form of the number thirty-one, describing a person or thing in position number 31 of a sequence.

   The answer appears on the thirty-first page of the book.

   She finished thirty-first in the race.

Usage notes

English ordinal numbers may function as either an adjective or as a noun, and almost never appear in the plural.

Abbreviations

• 31st, 31^st

Noun

thirty-first ‎(plural thirty-firsts)

1. (fractional) One of thirty-one equal parts of a whole.

   A thirty-first of 620 is 20.

Synonyms

• thirty-oneth