Definition of "eighty-first" in English

adjective

1. The ordinal form of the number eighty-one, describing a person or thing in position number 81 of a sequence.

   • The answer appears on the eighty-first page of the book.
   • She finished eighty-first in the race.

noun

1. One of eighty-one equal parts of a whole.

   • An eighty-first of 1620 is 20.