Source : Webster's Revised Unabridged Dictionary (1913)

Trichromatic \Tri`chro*mat"ic\, a. [Pref. tri- + chromatic.]
   (Zo["o]l.)
   Having or existing in three different phases of color; having
   three distinct color varieties; -- said of certain birds and
   insects.

Source : WordNet®

trichromatic
     adj : having or involving three colors; "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" [syn: {trichrome}, {tricolor}]