1. A dispersion in the air of a substance that is a liquid or a solid in its normal state; such as, water.
2. A gas whose temperature is less than the critical temperature, so that it may be converted to a liquid or solid by compression at a constant temperature.

1. An electric lamp in which the light comes from an electric discharge between two electrodes in a glass tube.
2. A lamp in which light is produced by an electric discharge between electrodes in a gas (or vapor) at low or high pressure.
3. A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and argon lamps are examples of electric-discharge lamps.
4. A lamp whose light is produced by current flow through a gas or vapor in a sealed glass enclosure.

Examples of these lamps include argon glow, mercury-vapor, neon glow, and sodium-vapor.

A substance suspended in the air, the temperature and pressure of which, are such that any compression of its volume at constant temperature causes it to condense to liquid at a rate sufficient to maintain a constant pressure.

A process used to remove salt from seawater, by evaporating it through a fine mesh filter that traps the brine particles so that the fluid can then be condensed into a relatively salt-free solution.

Another term for absolute humidity; that is, the mass of moisture in relation to the unit volume of space that it occupies.

The interruption of a flow of liquid with the formation of thin moisture, or gas bubbles, in a conduit; especially, an obstruction of this type in the flow of gasoline to the engine in a motor vehicle.

1. The pressure at which a liquid and its moisture particles are equal to each other at a given temperature.
2. The pressure exerted by mist, or clouds, in the atmosphere which are independent of any other gases or water particles.

The process of capturing chemical fumes; especially, for the purpose of reducing pollution: "Attempts at vapor recovery is being made with the gasoline vapor that is generated by the fueling of vehicles at gas stations."

A special gas pump spout that reduces the release of gasoline fumes into the air when vehicles are being refueled at a gas station.

A barrier applied to a surface to prevent moisture from migrating into, or out, of a given space: "A vapor seal is a moisture-impervious layer; such as, plastic film, vinyl, or vapor-retardant paint."

A description of a high-temperature hydrothermal system in which mixed water and steam exist, and steam is the pressure-controlling fluid phase: "Vapor-dominated systems; such as, "The Geysers" in northern California, are relatively rare but have high heat content and are well suited for the production of electrical power; while the more common liquid-dominated systems have lower heat content and are suited for direct heat uses."

In medicine, a very thin layer of material, usually transparent, through which oxygen and liquid can pass: "Vapor-permeable membranes may be prepared with an adhesive backing that will stick only to dry skin. This type of vapor-permeable membrane has been used in treating wounds."

A vapor-permeable membrane must be applied properly without wrinkles and changed as often as necessary to prevent an excess accumulation of fluid and bacteria under it.