water-filled device fitted into a rubber stopper of the fermenter, and acts as a barrier to oxygen and other things(dust, bacteria, molds) as well as a gate for escaping carbon dioxide.

A one way valve that allows co2 to escape but no air to get in during fermentation.

a device which allows carbon dioxide to escape during fermentation without letting oxygen or unwanted organisms in

a simple plastic device that allows the fermentation gases (carbon dioxide) to bubble through water to escape

A device to allow air out of the fermenter but prevent bugs and oxygen back into it.

A device placed on a fermenter (usually a carboy) for the purpose of allowing carbon dioxide to escape the vessel during the fermentation process. Since the airlock is filled with a liquid (commonly water, but you could use glycerin too), it works like a check valve; CO2 can escape, but O2 can't get in and oxidize your wine.

(Fermentation Lock): A device that attaches to the top of a fermentation barrel or carboy that allows C02 to escape out of an airtight connection but prevents bacteria from entering.

Term generally applied to a rotary vane valve that keeps air from entering a dust collector, yet allows collected particulate to continuously discharge from the device.

In homebrewing and winemaking, a one way valve, usually made of glass or plastic, fitted into centrally pierced cork or rubber bung, and attached to the mouth of the carboy to allow carbon dioxide gas to escape from the carboy while excluding ambient wild yeasts, bacteria, and other contaminants generally associated with prolonged exposure to air.

Airlocks are one-way valves in the leading edge of the wing, of a ram-air parachute. Panels of fabric are positioned at an angle to the leading edge of the wing such that air is allows to flow in, but not out. This reduces the rate of depressurization of the airfoil, which enhances safety when flying in turbulent conditions near the ground.

a chamber that enables people and things to move or be moved between volumes with different pressures; like a lock in a canal, the chamber starts at the pressure that the occupant is moving from, and changes to the pressure being moved to.

An airlock is a device which permits the passage of objects, people, and the like, between a pressure vessel and its surrounding space while minimizing the change of pressure—and loss of air—in the vessel. The lock consists of two airtight doors in series which do not open simultaneously.