Not even Sir William Crookes's vacua can give an idea of the rarefaction which this fact implies.
1540s, "emptiness of space," from Latin vacuum "an empty space, void," noun use of neuter of vacuus "empty," related to vacare "be empty" (see vain). Properly a loan-translation of Greek kenon, literally "that which is empty." Meaning "a place emptied of air" is attested from 1650s. Vacuum tube is attested from 1859. Vacuum cleaner is from 1903; shortened form vacuum (n.) first recorded 1910.
"to clean with a vacuum cleaner," 1922; see vacuum (n.). Related: Vacuumed; vacuuming.
vacuum vac·u·um (vāk'yōō-əm, -yōōm, -yəm)
n. pl. vac·u·ums or vac·u·a (-yōō-ə)
Absence of matter.
A space empty of matter.
A space relatively empty of matter.
A space in which the pressure is significantly lower than atmospheric pressure.
Plural vacuums or vacuua
The absence of matter.
Note: In the natural world, air will flow into regions of vacuum, giving rise to the saying “Nature abhors a vacuum.”
Note: The saying is extended informally: in politics, a lack of leadership may be referred to as a vacuum, which will presumably be filled by others rushing in.