Source : Webster's Revised Unabridged Dictionary (1913)

Trimorphic \Tri*mor"phic\, Trimorphous \Tri*mor"phous\, a. [Gr.
   ? three-formed; ? (see {Tri-}) + ? form.]
   Of, pertaining to, or characterized by, trimorphism; --
   contrasted with {monomorphic}, {dimorphic}, and
   {polymorphic}.