Definition of trefoil in English:


Pronunciation: /ˈtriːfɔɪl//ˈtrɛfɔɪl/


  • 1A small European plant of the pea family, with yellow flowers and three-lobed clover-like leaves.

    • ‘This ancient breed (Neolithic bones reveal its ancestry here) graze on heather grassland rich with wild flowers and herbs such as thyme, violets, orchids, primroses or bird's foot trefoil.’
    • ‘In its first year, the Buzz Project found that in fields containing margins of natural clovers and trefoils an average 1,850 bumble bees were found per hectare.’
    • ‘Saint Patrick used a seamróg, called a trefoil or three-leaf clover, to illustrate the concept of the trinity to the people.’
    • ‘Because trefoils are legumes, they fix nitrogen into the soil for later use by grasses and forbs.’
    • ‘Her sea-pinks, meadow-sweet, hairbells, daisies, trefoils, orchids and clovers are all still there in a rich rug of purples, blues, pinks, yellows and creams.’
    1. 1.1A plant with three-lobed leaves that is similar or related to the trefoil.
      • ‘It is sometimes called wild chervil; and also has the names honewort (used of the closely related C. canadensis in N. America) and trefoil (but this last is used of other plants also).’
    2. 1.2An ornamental design of three rounded lobes like a clover leaf, used typically in architectural tracery.
      [as modifier] ‘trefoil windows’
      • ‘In addition, the top areas of the main windows are decorated with stone tracery describing trefoils, quatrefoils and Moorish arches.’
      • ‘To this fusion are added Gothic style elements in the legs (a rounded arch above and a trefoil below each), colorful French ceramics with a Moorish flavor, and exotic serpents on either side of the ceramic cylinder.’
      • ‘At the tops of the windows, the artist has fun with the trefoils and quatrefoils, turning one into a black flower with yellow petals and another into a hovering cartoonlike form ringed by orange dots.’
      • ‘Although the trefoil, bell, and other tracery figures had previously appeared in mural decoration, they acquired exceptional importance around 1500.’
      • ‘Rather like the Venetians - the difference being that Venice went on evolving: its Byzantine ogees and trefoils made room for Palladio and all that.’
      • ‘The trefoil within the upper squares finds no counterpart above Gideon and the Burning Bush, though the tracery here falsely suggests an answering trefoil.’
    3. 1.3A thing having three parts; a set of three.
      ‘a trefoil of parachutes lowers the shuttle's used rockets to Earth’


Middle English: from Anglo-Norman French trifoil, from Latin trifolium, from tri- three + folium leaf.