any of a genus (Petunia) of plants of the nightshade family, with funnel-shaped flowers of various colors and patterns, esp. a common garden annual (P. hybrida)
See petunia in American Heritage Dictionary 4
(pĭ-to͞onˈyə, -tyo͞onˈ-)
noun
Any of various widely cultivated South American plants of the genus Petunia, having alternate, entire leaves and funnel-shaped flowers in colors from white to purple.