What is "tertiary color"

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.)

   1. The first period of the age of mammals, or of the Cenozoic era.

   2. 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.

n. (alternative spelling of tertiary colour English)

A tertiary color is a color made by mixing full saturation of one primary color with half saturation of another primary color and none of a third primary color, in a given color space such as RGB, CMYK (more modern) or RYB (traditional).

Tertiary colors have specific names, one set of names for the RGB color wheel and a different set for the RYB color wheel. These names are shown below.

Brown and grey colors can be made by mixing complementary colors.