[sham-rok] 
| any of several trifoliate plants, as the wood sorrel, Oxalis acetosella, or a small, pink-flowered clover, Trifolium repens minus, but esp. Trifolium procumbens, a small, yellow-flowered clover: the national emblem of Ireland. |
| sham·rock (shām'rŏk') n. Any of several plants, such as a clover or wood sorrel, having compound leaves with three small leaflets, considered the national emblem of Ireland. [Irish Gaelic seamróg, diminutive of seamar, clover, from Middle Irish semar.] |
shamrock
any of several similar-appearing trifoliate plants-i.e., plants each of whose leaves is divided into three leaflets. Plants called shamrock include the wood sorrel (Oxalis acetosella) of the family Oxalidaceae, or any of various plants of the pea family (Fabaceae), including white clover (Trifolium repens), suckling clover (T. dubium), and black medic (Medicago lupulina). According to Irish legend, St. Patrick, patron saint of Ireland, first chose the shamrock as a symbol of the Trinity of the Christian church because of its three leaflets bound by a common stalk. Wood sorrel is shipped from Ireland to other countries in great quantity for St. Patrick's Day
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