noun the tertiary era, period, or formation.
2. tertiary ·adj later than, or subsequent to, the secondary.
3. tertiary ·adj growing on the innermost joint of a bird's wing; tertial;
said of quills.
4. tertiary ·adj being of the third formation, order, or rank; third; as, a tertiary use of a word.
5. tertiary ·noun one of the quill feathers which are borne upon the basal joint of the wing of a bird. ·see ·illust. of bird.
6. tertiary ·adj 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.
7. tertiary ·noun 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.