Is “Trefoil” a Scrabble word?
Yes
TREFOIL
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Trefoil
/ˈtɹiː.fɔɪl/
noun
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.
noun
1.A knot formed by joining the two loose ends of a overhand knot to form a knotted loop; the simplest non-trivial knot.