ordinal(n = noun.quantity) no., ordinal number - the number designating place in an ordered sequence;
is a kind of number
has particulars: first, number 1, number one
Derived form adjective ordinal₂

1.  ordinal(a = adj.pert) - of or relating to a taxonomic order; "family and ordinal names of animals and plants"

2.  ordinal(a = adj.all) - being or denoting a numerical order in a series; "ordinal numbers"; "held an ordinal rank of seventh"
Antonym: cardinal
Derived form noun ordinal₁

1.  Indicating order or succession; as, the ordinal numbers, first, second, third, etc. Contrasted to cardinal. [1913 Webster]

2.  Of or pertaining to an order. [1913 Webster]

1.  A word or number denoting order or succession. [1913 Webster]

2.  The book of forms for making, ordaining, and consecrating bishops, priests, and deacons. [1913 Webster]

3.  A book containing the rubrics of the Mass. [1913 Webster]

ordinal, n. & adj.
--n.
1 (in full ordinal number) a number defining a thing's position in a series, e.g. 'first', 'second', 'third', etc. (cf. CARDINAL).
2 Eccl. a service-book, esp. one with the forms of service used at ordinations.
--adj.
1 a of or relating to an ordinal number. b defining a thing's position in a series etc.
2 Biol. of or concerning an order (see ORDER n. 8).

Etymology:
ME f. LL ordinalis & med.L ordinale neut. f. L (as ORDER)

ordinal number