—n. 1. a space entirely devoid of matter.
2. an enclosed space from which matter, esp. air, has been partially removed so that the matter or gas remaining in the space exerts less pressure than the atmosphere (opposed to plenum).
3. the state or degree of exhaustion in such an enclosed space.
4. a space not filled or occupied; emptiness; void: The loss left a vacuum in his heart. 5. a vacuum cleaner or sweeper.
6. Physics.a state of lowest energy in a quantum field theory.
—adj. 1. of, pertaining to, employing, or producing a vacuum.
2. (of a hollow container) partly exhausted of gas or air.
3. pertaining to a device or process that makes use of a vacuum to accomplish a desired task.
4. noting or pertaining to canning or packaging in which air is removed from the container to prevent deterioration of the contents.
—v.t. 1. to use a vacuum cleaner on; clean with a vacuum cleaner: to vacuum rugs. 2. to treat with any vacuum device, as a vacuum drier.
—v.i. to use a vacuum cleaner: to vacuum in the dining room.