trefoil

noun

tre·​foil ˈtrē-ˌfȯi(-ə)l  ˈtre- 

1

a

: clover sense 1

broadly : any of several leguminous herbs (such as bird's-foot trefoil) with leaves that have or appear to have three leaflets

b

: a trifoliolate leaf

2

: an ornament or symbol in the form of a stylized trifoliolate leaf

Illustration of trefoil

• trefoil 2

Examples of trefoil in a Sentence

Recent Examples on the Web

How long does a rope have to be in order to form a trefoil knot? —Kevin Hartnett, Quanta Magazine, 5 Jan. 2024

The simplest torus knot — indeed, the simplest nontrivial knot, period — is called a trefoil. —Kevin Hartnett, Quanta Magazine, 5 Jan. 2024

The mathematics of knot theory says that a simple loop and a trefoil are fundamentally different knots. —George Hart, Scientific American, 22 Jan. 2013

This flotation device served as the machine’s hull in the water, and was shaped like a trefoil to leave room for the airflow of the rotors. —IEEE Spectrum, 10 July 2023

Word History

Etymology

Middle English, from Anglo-French, from Latin trifolium, from tri- + folium leaf — more at blade

First Known Use

15th century, in the meaning defined at sense 1a

Phrases Containing trefoil

• bird's-foot trefoil
• tick trefoil

Kids Definition

trefoil

noun

tre·​foil ˈtrē-ˌfȯil  ˈtref-ˌȯil 

1

: any of several herbs (as a clover) of the legume family with leaves that have or appear to have three leaflets

2

: an ornament or symbol shaped like a leaf with three parts