A space in which the pressure is significantly lower than atmospheric pressure, a kind of continuous brake operated by exhausting the air from some appliance under each car, and so causing the pressure of the atmosphere to apply the brakes, the absence of matter, verb_ clean with a vacuum cleaner, transitive To clean (something) with a vacuum cleaner, intransitive To use a vacuum cleaner, adjective_ Of, relating to, or used to create a vacuum, Containing air or other gas at a reduced pressure, Operating by means of suction or by maintaining a partial vacuum