Definition of tertiary
			
									- a. - Being of the third formation, order, or rank; third; as,
   a tertiary use of a word.
- a. - 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.
- a. - Later than, or subsequent to, the Secondary.
- a. - Growing on the innermost joint of a bird's wing; tertial;
   -- said of quills.
- n. - 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.
- n. - The Tertiary era, period, or formation.
- n. - One of the quill feathers which are borne upon the basal
   joint of the wing of a bird. See Illust. of Bird.