n. [ Supposed to be brought from Guelderland; hence, D. Geldersche roos, G. Gelderische rose, F. rose de Gueldre, It. rose di Gueldra, Sp. rosa de Gueldres. ] (Bot.) A cultivated variety of a species of Viburnum (V. Opulus), bearing large bunches of white flowers; -- called also snowball tree.

{ } n. [ It. Guelfo, from Welf, the name of a German family. ] (Hist.) One of a faction in Germany and Italy, in the 12th and 13th centuries, which supported the House of Guelph and the pope, and opposed the Ghibellines, or faction of the German emperors.

{ } a. Of or pertaining to the family or the faction of the Guelphs. [ 1913 Webster ]