four-leaf clover

US: (fôr′lēf′, fōr′-)

WordReference Random House Unabridged Dictionary of American English © 2025

four′-leaf clo′ver  (fôr′lēf′, fōr′-), 

1. a clover leaf having four leaflets instead of the usual three, purported to bring good luck.

• 1840–50

Collins Concise English Dictionary © HarperCollins Publishers::

four-leaf clover, four-leaved clover noun

1. a clover with four leaves rather than three, supposed to bring good luck
2. another name for cloverleaf1