interj.

Used to call attention to or express satisfaction with a thing shown or accomplished: Mix the ingredients, chill, and—voilà!—a light, tasty dessert.

[French : voi, second person sing. imperative of voir, to see (from Old French; see voyeur) + là, there (from Old French la, lai, probably from Latin illāc, by that way : illā, ablative sing. feminine of ille, that + -ce, deictic particle).]

IN BRIEF: There it is; There you are.