Source : Webster's Revised Unabridged Dictionary (1913)

Petunia \Pe*tu"ni*a\, n. [NL., fr. Braz. petun tobacco.] (Bot.)
   A genus of solanaceous herbs with funnelform or salver-shaped
   corollas. Two species are common in cultivation, {Petunia
   violacera}, with reddish purple flowers, and {P.
   nyctaginiflora}, with white flowers. There are also many
   hybrid forms with variegated corollas.

Source : WordNet®

petunia
     n : any of numerous tropical herbs having fluted funnel-shaped
         flowers