1 cease from agitation; become tranquil; abate (excitement subsided).
2 (of water, suspended matter, etc.) sink.
3 (of the ground) cave in; sink.
4 (of a building, ship, etc.) sink lower in the ground or water.
5 (of a swelling etc.) become less.
6 usu. joc. (of a person) sink into a sitting, kneeling, or lying posture.
Derivatives:
subsidence n.
Etymology: L subsidere (as SUB-, sidere settle rel. to sedere sit)
Useful english dictionary. 2012.