1. Civ. Eng.an airtight chamber permitting passage to or from a space, as in a caisson, in which the air is kept under pressure.
2. the impedance in the functioning of a pump or a system of piping caused by the presence of an air bubble; vapor lock.
Pronunciation: (âr'lok"), [key]
to place in or confine to an air lock: to air-lock divers before they descend.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.