Definition of "vacuum" in 英语

noun

1. A region of space that contains no matter.

2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, such as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.

   • a vacuum of 26 inches of mercury, or 13 pounds per square inch

3. (colloquial, only pluralized as "vacuums") Ellipsis of vacuum cleaner.

4. (physics) A spacetime having tensors of zero magnitude.

5. (physics) A ground state of a quantum field or of local spacetime, or more abstractly the lowest-energy state of a system.

6. An emptiness in life created by a loss of a person who was close, or of an occupation.

7. An exercise in which one draws their abdomen towards the spine.

verb

1. (transitive) To clean (something) with a vacuum cleaner.

2. (intransitive) To use a vacuum cleaner.

3. (transitive, databases) To optimise a database or database table by physically removing deleted tuples.