tertiary Meaning, Definition & Usage

noun from 63 million to 2 million years ago
Tertiary period.
adjective satellite coming next after the second and just before the fourth in position
3rd; third.

L. tertiarius containing a third part, fr. tertius third: cf. F. tertiaire. See Tierce.

Being of the third formation, order, or rank; third; as, a tertiary use of a word. Trench.
(Chem.) Possessing some quality in the third degree; having been subjected to the substitution of three atoms or radicals; as, a tertiary alcohol, amine, or salt. Cf. Primary, and Secondary. specifically, an organic compound in which teh carbon atom attached to the eponymic functional group has three carbon atoms attached to it; as, tertiary butyl alcohol, (CH3)3C.OH.
(Geol.) Later than, or subsequent to, the Secondary.
(Zoöl.) Growing on the innermost joint of a bird's wing; tertial; -- said of quills.

plural Tertiaries

(R. C. Ch.) A member of the Third Order in any monastic system; as, the Franciscan tertiaries; the Dominican tertiaries; the Carmelite tertiaries. See Third Order, under Third. Addis & Arnold.
(Geol.) The Tertiary era, period, or formation.
(Zoöl.) One of the quill feathers which are borne upon the basal joint of the wing of a bird. See Illust. of Bird.