Trefoil (from Latin trifolium, "three-leaved plant", French trèfle, German Dreiblatt and Dreiblattbogen) is a graphic form composed of the outline of three overlapping rings used in architecture and Christian symbolism. The term is also applied to other symbols of three-fold shape. Architecture Trefoil is a term in Gothic architecture given to the ornamental foliation or cusping introduced in the heads of window-lights, tracery, panellings, etc., in which the center takes the form of a t… (More on Trefoil)