Quenching

[1] Dipping a heated object into water, oil or other substance, to quickly reduce the temperature. Quenching into water gives a more rapid cooling rate than into oil. The term also applies to cooling in salt and molten-metal baths or by means of an air blast. Applied to steels heated above their upper critical temperature in order to harden them prior to tempering and to other alloys for solution treatment prior to precipitation hardening.
[2] A nuclear engineering term to describe the process of inhibiting continuous discharge, by choice of gas and/or external valve circuit, so that discharge can occur again on the incidence of a further photon or particle in a counting tube.
[3] A suppression of oscillation, particularly periodically, as in a super-regenerative receiver.