A shamrock is a small plant with three round leaves on each stem. The shamrock is the national symbol of Ireland.
shamrock in British English
(ˈʃæmˌrɒk)
noun
a plant having leaves divided into three leaflets, variously identified as the wood sorrel, red clover, white clover, and black medick: the national emblem of Ireland
Word origin
C16: from Irish Gaelic seamrōg, diminutive of seamar clover
shamrock in American English
(ˈʃæmˌrɑk)
noun
any of certain clovers or cloverlike plants with leaflets in groups of three, used as the emblemof Ireland, as the red clover, white clover, wood sorrel, or black medic