tricolor

(noun) a flag having three colored stripes (especially the French flag). Synonyms: tricolour.

(adj) having or involving three colors. Synonyms: trichromatic, trichrome. Examples: "Trichromatic vision." "A trichromatic printing process." "Trichromatic staining is the staining of tissue samples differentially in three colors." "Tricolor plumage." "A tricolor process in photography."