(1):

(v. i.) To sink or fall to the bottom; to settle, as lees.

(2):

(v. i.) To tend downward; to become lower; to descend; to sink.

(3):

(v. i.) 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.