The Collaborative International Dictionary of English v.0.48:
Subside \Sub*side"\, v. i. [imp. & p. p. Subsided; p. pr. &
vb. n. Subsiding.] [L. subsidere; sub under, below + sidere
to sit down, to settle; akin to sedere to sit, E. sit. See
1. To sink or fall to the bottom; to settle, as lees.
2. To tend downward; to become lower; to descend; to sink.
"Heaven's subsiding hill." --Dryden.
3. To fall into a state of quiet; to cease to rage; to be
calmed; to settle down; to become tranquil; to abate; as,
the sea subsides; the tumults of war will subside; the
fever has subsided. "In cases of danger, pride and envy
naturally subside." --C. Middleton.
Syn: See Abate.
[1913 Webster] Subsidence