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

Illustration of trefoil

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 At the forefront of the phenomenon is the sportswear giant Adidas, which has been generous with its famous insignia, inviting mega-brands and superstar designers alike, not to mention skaters and hip-hop impresarios, to twist, turn, and otherwise hybridize the iconic trefoil. Tiziana Cardini, Vogue, 7 June 2022 Fashionable mashups include Adidas’ three white stripes and trefoil logo with Gucci’s red and green motif and intertwined logo pattern, as seen in tailored tracksuits, sweats sets, oversized emerald green hoodies, T-shirt dresses, V-neck tees, Gazelle sneakers in GG canvas and more. Danielle Directo-Meston, The Hollywood Reporter, 6 June 2022 The Tonale proudly wears Alfa Romeo's signature trefoil grille. Jonathan M. Gitlin, Ars Technica, 8 Feb. 2022 But the cyanide-making genes of the trefoil and the moth take these disparities to a whole new level. Ed Yong, Discover Magazine, 12 Apr. 2011

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'trefoil.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Time Traveler
The first known use of trefoil was in the 15th century

Dictionary Entries Near trefoil

Cite this Entry

“Trefoil.” Dictionary, Merriam-Webster, Accessed 15 Apr. 2024.

Kids Definition


: any of several herbs (as a clover) of the legume family with leaves that have or appear to have three leaflets
: an ornament or symbol shaped like a leaf with three parts

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