trefoil

n 1 any of various types of plant with three leaves on each stem (eg clover) 三叶草（如车轴草）. 2 ornament or design shaped like such a leaf 三叶形装饰或图案.

treasure-hunt, treasurer, treasury, Treasury bill, treat, treat sb. as, treat sb. for, treatable, treatise, treatment, treaty, treble, treble chance, tree, tree-fern, tree-house, tree-line (also `timber-line), tree-top, tree-trunk, treeless, trek, trellis, tremble, trembler, trembling, trembly, tremella, tremendous, tremendously, tremolo, tremor, tremulous, tremulously, trench, trench coat, trenchant, trenchantly, trencher, trencherman, trend,