ordinal number: Meaning and Definition of

or'dinal num'ber

Pronunciation: [key]
  1. Also calledany of the numbers that express degree, quality, or position in a series, as first, second, and third (distinguished from cardinal number).
  2. a symbol denoting both the cardinal number and the ordering of a given set, being identical for two ordered sets having elements that can be placed into one-to-one correspondence, the correspondence preserving the order of the elements.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.