[ tree-foil, tref-oil ]
/ ˈtri fɔɪl, ˈtrɛf ɔɪl /
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any of numerous plants belonging to the genus Trifolium, of the legume family, having usually digitate leaves of three leaflets and reddish, purple, yellow, or white flower heads, comprising the common clovers.
any of various similar plants.
Architecture. an ornament composed of three lobes, divided by cusps, radiating from a common center.
such an ornamental figure used by the Girl Scouts as its official emblem.


of, relating to, or shaped like a trefoil.



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Origin of trefoil

1350–1400; Middle English <Anglo-French trifoil<Latin trifolium triple leaf, the three-leaved plant, clover, equivalent to tri-tri- + folium leaf
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for trefoil

/ (ˈtrɛfɔɪl) /


any of numerous leguminous plants of the temperate genus Trifolium, having leaves divided into three leaflets and dense heads of small white, yellow, red, or purple flowers
any of various related plants having leaves divided into three leaflets, such as bird's-foot trefoil
a leaf having three leaflets
architect an ornament in the form of three arcs arranged in a circle
trefoiled, adjective
C14: from Anglo-French trifoil, from Latin trifolium three-leaved herb, from tri- + folium leaf
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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