Used to call attention to or express satisfaction with something that is presented or something that has been accomplished: Mix the ingredients, chill, and—voilà!—a light, tasty dessert.
an expression of satisfaction
or voi•la(vwɑˈlɑ; Fr. vwaˈla)
(used to express success or satisfaction.)
[1825–35; < French]
A French word meaning see there, used to draw attention to something.