Meaning

noun small pieces or streamers of colored paper that are thrown around on festive occasions (as at a wedding)

originBorrowed (possibly via French) from Italian confetti (literally “confections”), used to describe sugar-coated almonds, and by extension things imitating them (like pellets of plaster), which were thrown in Italy during festivities like Carnival and weddings. (This practice is mentioned in English since at least the 1810s.) The French and the English adopted the practice of celebrating weddings…

Etymology from Wiktionary, CC BY-SA 3.0