—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)
Useful english dictionary. 2012.