trefoil

noun

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

  • Genera Trifolium and Lotus, family Leguminosae: several species, in particular the bird’s-foot trefoil
• a plant with three-lobed leaves that is similar or related to the trefoil.
• an ornamental design of three rounded lobes like a clover leaf, used typically in architectural tracery: [as modifier]:trefoil windows
• a thing having three parts; a set of three:a trefoil of parachutes lowers the shuttle’s used rockets to Earth