vacuum, vacuity (noun)

the absence of matter

void, vacancy, emptiness, vacuum (noun)

an empty area or space

"the huge desert voids"; "the emptiness of outer space"; "without their support he'll be ruling in a vacuum"

vacuum, vacuity (noun)

a region that is devoid of matter

vacuum, vacuum cleaner (verb)

an electrical home appliance that cleans by suction

vacuum, vacuum-clean, hoover (verb)

clean with a vacuum cleaner

"vacuum the carpets"

vacuum (Noun)

A region of space that contains no matter.

vacuum (Noun)

A vacuum cleaner.

vacuum (Verb)

To clean (something) with a vacuum cleaner.

vacuum (Verb)

To use a vacuum cleaner.

Vacuum

Vacuum is space that is empty of matter. The word stems from the Latin adjective vacuus for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum. The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth of atmospheric pressure, and can reach around 100 particles/cm³. Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average. Some theories predict that even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, and other phenomena in quantum physics. In modern particle physics, the vacuum state is considered as the ground state of matter.