any of a genus (Hydrangea) of shrubs or vines of the saxifrage family, with opposite leaves and large, showy clusters of white, blue, or pink flowers, often sterile
Origin:
ModL < hydr- + Gr angeion, vessel
See hydrangea in American Heritage Dictionary 4
noun
Any of various shrubs of the genus Hydrangea, having opposite leaves and large, flat-topped or rounded clusters of white, pink, or blue flowers.