A three-leaved plant, typically clover, used as the national emblem of Ireland and symbol of St. Patrick's Day.
From Irish 'seamróg', diminutive of 'seamair' (clover), ultimately from Proto-Celtic. The association with St. Patrick comes from the legend that he used the three leaves to explain the Christian Trinity to the Irish.
Despite being Ireland's national symbol, botanists still debate which exact plant is the 'true' shamrock - different regions of Ireland claim different clover species. The four-leaf clover is actually not a shamrock at all, but a lucky mutation of the three-leafed variety that became associated with different folklore entirely.
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