Any of various herbs of the pea family (Fabaceae) that have three-lobed leaves, especially species in the genera Lotus and Trifolium such as bird's-foot trefoil (Lotus corniculatus).
Bird's-foot trefoil is a common trefoil that thrives in meadows and roadside verges.
An ornamental design of three rounded lobes, resembling a clover leaf, used typically in architectural tracery.
The cathedral's windows were adorned with intricate trefoil patterns.
A figure or knot consisting of three interlinked loops, specifically the simplest non-trivial mathematical knot.
The trefoil is the first example studied in introductory knot theory.
trefoiladjective
Having the shape or characteristics of a trefoil; three-lobed.