1. (a.) Being of the third formation, order, or rank; third; as, a tertiary use of a word.

2. (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.

3. (a.) Later than, or subsequent to, the Secondary.

4. (a.) Growing on the innermost joint of a bird's wing; tertial; -- said of quills.

5. (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.

6. (n.) The Tertiary era, period, or formation.

7. (n.) One of the quill feathers which are borne upon the basal joint of the wing of a bird.

Maxwell triangle Munsell scale chromatic circle chromatic spectrum chromaticity diagram color circle color cycle color index color mixture curve color solid color spectrum color system color triangle complementary color covert demitint feather feathers full color fundamental colors hackle half tint halftone hue cycle mail metamer monochrome plumage primary primary color pure color secondary secondary color solar spectrum spectral color spectrum spectrum color speculum tertiary color third