triform

from The Collaborative International Dictionary of English v.0.48

Triform \Tri"form\, a. [L. triformis; tri- (see {Tri-}) + forma
   form.]
   Having a triple form or character. "This triform antagonism."
   --I. Taylor.
   [1913 Webster]

         Goddess Triform, I own thy triple spell. --Lowell.
   [1913 Webster]