Source : Webster's Revised Unabridged Dictionary (1913)

Hydrangea \Hy*dran"ge*a\, n. [NL., fr. Gr. "y`dwr water + ?
   vessel, capsule: cf. F. hydrang['e]e.] (Bot.)
   A genus of shrubby plants bearing opposite leaves and large
   heads of showy flowers, white, or of various colors. {H.
   hortensis}, the common garden species, is a native of China
   or Japan.

Source : WordNet®

hydrangea
     n : any of various deciduous or evergreen shrubs of the genus
         Hydrangea