The shamrock refers to the young sprigs of clover or trefoil. It is known as a symbol of Ireland, with St. Patrick having used it as a metaphor for the Christian Trinity, according to legend. The name shamrock is derived from Irish seamróg, which is the diminutive version of the Irish word for clover (seamair) meaning simply "little clover" or "young clover".Shamrock is usually considered to refer to either the species Trifolium dubium (lesser clover, Irish: seamair bhuí) or Trifolium repens (white clover, Irish: seamair bhán). However, other three-leaved plants—such as Medicago lupulina, Trifolium pratense, and Oxalis acetosella—are sometimes called shamrocks or clovers. The shamrock was traditionally used for its medicinal properties and was a popular motif in Victorian times.