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ordinal number

noun
  1. Also called ordinal numeral. any of the numbers that express degree, quality, or position in a series, as first, second, and third (distinguished from cardinal number).
  2. Mathematics. 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.

Origin of ordinal number

First recorded in 1600–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for ordinal numbers

ordinal number

noun
  1. a number denoting relative position in a sequence, such as first, second, thirdSometimes shortened to: ordinal
  2. logic maths a measure of not only the size of a set but also the order of its elements
Compare cardinal number
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
ordinal numbers in Science

ordinal number

[ôr′dn-əl]
  1. A number, such as 3rd, 11th, or 412th, used in counting to indicate position in a series but not quantity. Compare cardinal number.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ordinal numbers in Culture

ordinal numbers

Numbers that indicate the order or position of something in a group or set, such as first, second, or fifteenth. (Compare cardinal numbers.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.