(1):

(v. t.) To extinguish; to overwhelm; to make an end of; - said of flame and fire, of things burning, and figuratively of sensations and emotions; as, to quench flame; to quench a candle; to quench thirst, love, hate, etc.

(2):

(v. t.) To cool suddenly, as heated steel, in tempering.

(3):

(v. i.) To become extinguished; to go out; to become calm or cool.