trefoil - Wiktionary, the free dictionary

From Middle English trefoil, from Old French trifoil, trefeul, from Latin trifolium, from tri- (“three”) + folium (“leaf”).

• IPA^(key): /ˈtɹɛ.fɔɪl/, /ˈtɹiː.fɔɪl/

trefoil (plural trefoils)

1. Any of several plants of the pea family, having compound, trifoliate leaves; especially one of the genus Trifolium.
2. A symbol having the shape of such leaves, especially when used as an architectural ornament.

   Synonym: threefoil
3. (topology) Ellipsis of trefoil knot.

• loftier