ordinal1

[awr-dn-uh l] /ˈɔr dn əl/
adjective
1.
of or pertaining to an order, as of animals or plants.
2.
of or pertaining to order, rank, or position in a series.
noun
3.
an ordinal number or numeral.
Origin
1590-1600; < Late Latin ōrdinālis in order equivalent to Latin ōrdin- (stem of ōrdō) order + -ālis -al1
Related forms
ordinally, adverb

ordinal2

[awr-dn-uh l] /ˈɔr dn əl/
noun
1.
a directory of ecclesiastical services.
2.
a book containing the forms for the ordination of priests, consecration of bishops, etc.
Origin
1350-1400; Middle English < Medieval Latin ōrdināle, noun use of neuter of ōrdinālis in order. See ordinal1
British Dictionary definitions for ordinal

ordinal

/ˈɔːdɪnəl/
adjective
1.
denoting a certain position in a sequence of numbers
2.
of, relating to, or characteristic of an order in biological classification
noun
3.
short for ordinal number
4.
a book containing the forms of services for the ordination of ministers
5.
(RC Church) a service book
Word Origin
C14: (in the sense: orderly): from Late Latin ordinalis denoting order or place in a series, from Latin ordōorder
Word Origin and History for ordinal
n.

early 14c., "book setting forth the order of services in the Church," from Late Latin adjective ordinalis (see ordinal (adj.)).

adj.

late 14c., "regular, ordinary," from Old French ordinel and directly from Late Latin ordinalis ""showing order, denoting an order of succession," from Latin ordo (genitive ordinis) "row, series" (see order (n.)). Meaning "marking position in an order or series" is from 1590s.

ordinal in Technology

mathematics
An isomorphism class of well-ordered sets.
(1995-03-10)