Pianissimo is a music word. It tells you to play or sing very quietly — quieter than piano, which already means softly. On a score it is often written pp. Players use it for a hush, a far-away sound, or a line that should barely sit in the air. It is Italian, like many marks in Western classical music, and it is at home in lessons, rehearsals, and concert notes; outside music it sounds like a joke or a flourish. It can be used as an adverb (play pianissimo) or as a noun for a very quiet passage (a sudden pianissimo). The opposite direction is forte and then fortissimo: loud, then very loud.

極弱、非常輕（樂譜上常標 pp；音樂班直接說 pianissimo）