trefoil

American  

[tree-foil, tref-oil] / ˈtri fɔɪl, ˈtrɛf ɔɪl /

noun

1. any of numerous plants belonging to the genus Trifolium, of the legume family, having usually digitate leaves of three leaflets and reddish, purple, yellow, or white flower heads, comprising the common clovers.

2. any of various similar plants.

3. Architecture. an ornament composed of three lobes, divided by cusps, radiating from a common center.

4. such an ornamental figure used by the Girl Scouts as its official emblem.

---

adjective

1. of, relating to, or shaped like a trefoil.

trefoil British  

/ ˈtrɛfɔɪl /

noun

1. any of numerous leguminous plants of the temperate genus Trifolium , having leaves divided into three leaflets and dense heads of small white, yellow, red, or purple flowers

2. any of various related plants having leaves divided into three leaflets, such as bird's-foot trefoil

3. a leaf having three leaflets

4. architect an ornament in the form of three arcs arranged in a circle

---

Other Word Forms

• trefoiled adjective

Etymology

Origin of trefoil

1350–1400; Middle English < Anglo-French trifoil < Latin trifolium triple leaf, the three-leaved plant, clover, equivalent to tri- tri- + folium leaf

Example Sentences

The researchers emphasize the incredibly high precision that the characterization process required, as the trefoil field is made of not just one, but two coherently combined optical fields.

From Science Daily • Apr. 24, 2024

The trefoil also appeared on big travel bags, and as a print on trousers.

From Seattle Times • Feb. 25, 2022

The butterfly may thrive in active quarries because its egg-laying plant of choice, birdsfoot trefoil, grows well in the parts that aren’t being excavated, Fartmann says.

From Science Magazine • Nov. 18, 2021

It was to be a 42-story, billion-dollar resort featuring “an exotic South Seas theme,” a swim-up shark exhibit and a trefoil footprint with a facade of gold leaf.

From Washington Post • Oct. 5, 2017

Bigwig followed Chervil along the run, down which came the scents of warm grass, clover and hop trefoil.

From "Watership Down: A Novel" by Richard Adams