þagnarbindindi

Etymology
From 🇰🇲.

Noun

 * 1) a temporary vow of silence, a period in which a person or a group intentionally does not utter a single word, quiet time in a classroom

Usage notes
Often used by elementary school teachers ("Einn, tveir, og þagnarbindindi!" – "Everybody, a period of complete silence in one, two, and ...") in order to turn staying silent into a game.