Tre"foil (?), n. [L. tres three + E. foil leaf; cf. F. frèfle, It. trifoglio, L. trifolium. See Tri-, Foil leaf, and cf. Trifoly.] 1. (Bot.) Any plant of the genus Trifolium, which includes the white clover, red clover, etc.; -- less properly, applied also to the nonesuch, or black medic. See Clover, and Medic.

2. (Arch.) An ornamental foliation consisting of three divisions, or foils.

3. (Her.) A charge representing the clover leaf.

Tre"foil (?), n. [L. tres three + E. foil leaf; cf. F. frèfle, It. trifoglio, L. trifolium. See Tri-, Foil leaf, and cf. Trifoly.] 1. (Bot.) Any plant of the genus Trifolium, which includes the white clover, red clover, etc.; -- less properly, applied also to the nonesuch, or black medic. See Clover, and Medic.

2. (Arch.) An ornamental foliation consisting of three divisions, or foils.

3. (Her.) A charge representing the clover leaf.

• any of several plants of the pea family, having compound, trifoliate leaves; especially one of the genus Trifolium
  
• a symbol having the shape of such leaves, especially when used as an architectural ornament