<p><strong>Noun:</strong></p><ul><li>Any of numerous plants belonging to the genus <em>Trifolium</em>, of the legume family, having usually digitate leaves of three leaflets and reddish, purple, yellow, or white flower heads, comprising the common clovers.</li><li>Any of various similar plants.</li><li>(Architecture) An ornament composed of three lobes, divided by cusps, radiating from a common center.</li><li>Such an ornamental figure used by the Girl Scouts as its official emblem.</li></ul><p><strong>Adjective:</strong></p><ul><li>Of, relating to, or shaped like a trefoil.</li></ul>