三叶草属 meaning in English — shamrock, trefoil

English meaning

shamrock noun A small clover leaf with three leaflets, widely used as a symbol of Ireland.
trefoil noun Any of several plants of the pea family, having compound, trifoliate leaves; especially one of the genus Trifolium.

三叶草属 is used for these senses in English:

cloverleaf interchange (US, Canada) A junction of two highways, one crossing over the other, having a series of exit and entrance ramps, arranged in the form of a four-leaf clover, such that traffic may proceed from either highway in all directions.
shamrock The trefoil leaf of any small clover, especially Trifolium repens, or such a leaf from a clover-like plant, commonly used as a symbol of Ireland.
trefoil Any of several plants of the pea family, having compound, trifoliate leaves; especially one of the genus Trifolium.

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