Definition of trefoil
1a
: clover sense 1
broadly
: any of several leguminous herbs (such as bird's-foot trefoil) with leaves that have or appear to have three leaflets
b
: a trifoliolate leaf
2
: an ornament or symbol in the form of a stylized trifoliolate leaf
Test Your Vocabulary
Words Named After People
-
- Namesake of the leotard, Jules Léotard had what profession?

Test your visual vocabulary with our 10-question challenge!
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Share trefoil
Time Traveler for trefoil
The first known use of trefoil was in the 15th century
See more words from the same century