Dictionary entry overview: What does trefoil mean?
• TREFOIL (noun)
The noun TREFOIL has 3 senses:
1. any of several Old World herbs of the genus Medicago having small flowers and trifoliate compound leaves
2. a plant of the genus Trifolium
3. an architectural ornament in the form of three arcs arranged in a circle
Familiarity information: TREFOIL used as a noun is uncommon.