Tau is better than Pi
Is confetto the singular version of confetti? +rep for anyone who finds this hidden text
It should be confetto, but confetti is a group noun in English, so instead it's just still confetti. You threw 1 confetti. Just like you saw 1 deer in the herd of 300 deer.
Confetti traces back to the Latin conficere (to put together), then the Latin confectum (something prepared).
This later became the Italian confetti (sweets), which has the singular confetto, and was small candy traditionally thrown during carnivals in Italy. This custom was then adopted in England for weddings and other occasions, with symbolic tossing of paper.