A region of space that contains no matter.

(plural only "vacuums") A vacuum cleaner.

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”

To clean (something) with a vacuum cleaner.

To use a vacuum cleaner.

To optimise a database or database table by physically removing deleted tuples.