Crossword Dictionary

What's The Definition Of Tertiary?

\Ter"ti*a*ry\, a. [L. tertiarius containing a third part, fr. tertius third: cf. F. tertiaire. See {Tierce}.] 1. Being of the third formation, order, or rank; third; as, a tertiary use of a word. --Trench. 2. (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}. 3. (Geol.) Later than, or subsequent to, the Secondary. 4. (Zo["o]l.) Growing on the innermost joint of a bird's wing; tertial; -- said of quills. {Tertiary age}. (Geol.) See under {Age}, 8. {Tertiary color}, a color produced by the mixture of two secondaries. ``The so-called tertiary colors are citrine, russet, and olive.'' --Fairholt. {Tertiary period}. (Geol.) (a) The first period of the age of mammals, or of the Cenozoic era. (b) The rock formation of that period; -- called also {Tertiary formation}. See the Chart of {Geology}. {Tertiary syphilis} (Med.), the third and last stage of syphilis, in which it invades the bones and internal organs.
\Ter"ti*a*ry\, n.; pl. {Tertiaries}. 1. (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. 2. (Geol.) The Tertiary era, period, or formation. 3. (Zo["o]l.) One of the quill feathers which are borne upon the basal joint of the wing of a bird. See Illust. of {Bird}.