Definition of ordinal in US English:



  • 1

    short for ordinal number
    • ‘Having solved the open problem posed by Davenport on writing numbers as the sums of fifth powers, Conway began to become interested in infinite ordinals.’
    • ‘Form numbers are conceived as ordinals, with units conceived as being well ordered.’
    • ‘In his work he clarified a remark by Russell and formulated precisely the paradox of the largest ordinal.’
    • ‘In 1907 he introduced special types of ordinals in an attempt to prove Cantor's continuum hypothesis.’
    • ‘In this latter book she presented a 30 page appendix on the theory of infinite cardinals and ordinals.’
  • 2Christian Church
    historical A service book, especially one with the forms of service used at ordinations.

    • ‘The report continues with a discussion of the various ministries of deacons, including the basis as expressed in the ordinal at ordination in a new trial liturgy in the Diocese of Salisbury.’


  • 1Relating to a thing's position in a series.

    ‘ordinal position of birth’
    • ‘Data indicating familial and ordinal positions are not available.’
    • ‘The Mann-Whitney U test is appropriate when the independent variable has two levels and the dependent variable is measured on an ordinal scale.’
    • ‘To account for this bias, we transformed the outcome variables to an ordinal scale with 5 categories.’
    • ‘The answers were transformed to an ordinal scale with values from 0 to 6.’
    • ‘Children were asked whether they could determine, based on their ordinal position within different classes and families, which of two turtles was faster or taller.’
    1. 1.1 Relating to an ordinal number.
    2. 1.2Biology Relating to a taxonomic order.
      • ‘The present study suggests that tube-foot morphology may be useful as a taxonomic character at the ordinal level.’
      • ‘It is difficult to establish an accurate ordinal assignment of the taxa described above based on the current knowledge.’
      • ‘Mammalian phylogenetics at the ordinal level remains one of the outstanding problems in systematics because of the lack of congruence between different data sets.’
      • ‘The same procedure was followed for the two most abundant taxa identified at the ordinal level.’
      • ‘While all of the phyla but one were established during the Cambrian explosion, taxonomic increases during the Ordovician were manifest at lower taxonomic levels although ordinal level diversity doubled.’


Middle English (in ordinal (sense 2 of the noun)): the noun from medieval Latin ordinale (neuter); the adjective from late Latin ordinalis ‘relating to order in a series’, from Latin ordo, ordin- (see order).