A position is quiet if each live group is quiet.
Quiescence imagines representative sequences that make all important groups stable and settled.
Robert Jasiek: Should quiescence get its own page?
tapir: Who gets double sente when applying quiescence?
Robert Jasiek: Why double sente? Consider each quiescence sequence (one reducing Black's territory - one reducing White's) separately!
tapir: Guess I need an example.