vacuum
Pluralvacuums
Verbvacuums, vacuuming, vacuumed
Pluralvacuums
Formsvacuums, vacuuming, vacuumed
- 1A region of space empty of all matter.
Without air resistance, a feather and a hammer fall at the same rate in a vacuum.
The bell jar created a near vacuum around the ringing alarm.
Oppositeplenum
Note
The root sense, and the one the Latin carries most plainly: vacuum is a noun made from vacuus, "empty," kin to vacāre, "to be empty." Its opposite is plenum, space filled with matter, and void is a plainer near-synonym. It works as a count noun (a vacuum) and as a mass noun, as when towers in BioWare's Mass Effect (2007) are "sealed against vacuum." The formal plural vacua is rare.
- 2Shortened form of vacuum cleaner.
She dragged the vacuum up the stairs to clean the bedrooms.
Our new vacuum barely makes any noise.
Note
A household clipping of vacuum cleaner, at home in casual speech. Whatever the scientific senses allow, this one always takes the plural vacuums: nobody owns two vacua. British speakers often say hoover instead, borrowing the name for the machine and, as a verb, for using it.
- 3To clean something by going over it with a vacuum cleaner.
Volunteers vacuum the hall after every event.
He vacuumed the car seats to get rid of the sand.
Similarhoover
Note
The verb keeps the doubled u through every form: vacuums, vacuumed, vacuuming. Writers often drop one u by mistake. Used transitively, it takes the thing cleaned as its object (vacuuming a shed, vacuum the carpet), while the bare household verb stands without one.
- 4To do household cleaning by operating a vacuum cleaner.
They vacuum all over the house on weekends.
He vacuums while listening to music.
Similarhoover
- 5An emptiness in one's life left by the loss of a close person or of an occupation.
The founder's departure left a vacuum at the top of the company.
After the children moved out, she felt a strange vacuum in her days.
Similarvoid, gap, emptiness, hole, vacancy
Note
The figurative extension of empty space into a life: what is gone leaves room that nothing fills. It typically comes with left by, which names what was lost. In Letitia Elizabeth Landon's Ethel Churchill (1837), Henrietta's vacuum is left by the letters she used to write to her uncle, so the loss can be a habit or occupation as much as a person.
- 6A reduction of pressure inside a vessel to well below that of the surrounding atmosphere, as in the condenser of a steam engine.
The condenser maintains a partial vacuum to improve the engine's efficiency.
Operators measured the vacuum in the vessel with a gauge.
Note
Here vacuum is a quantity, not an absolute. Engineers speak of how much vacuum a vessel holds and measure it as a shortfall of pressure: "a vacuum of 26 inches of mercury, or 13 pounds per square inch." Unlike the ideal of empty space, this sense comes in degrees, which is why it pairs so readily with numbers and gauges.
- 7An abdominal exercise in which one draws the belly inward toward the spine and holds the contraction.
He added the vacuum to his routine to train his deep abdominal muscles.
Hold the vacuum while breathing slowly to engage the transverse abdominals.
Note
A bodybuilder's word that covers both the drill and the display. Lifters practice their vacuum or do a gut vacuum in training. On stage, the vacuum pose, or vacuum shot, shows a pulled-in waist, and Arnold Schwarzenegger's Encyclopedia of Modern Bodybuilding (1985) lists it beside the most-muscular shot. As a modifier before pose or shot, it names the competition move rather than the exercise.
- 8A region of spacetime whose tensors have zero magnitude, describing space free of matter and energy.
The Schwarzschild solution describes the vacuum surrounding a non-rotating mass.
Gravitational waves can travel through a vacuum where no matter exists.
Note
A physicist's term from general relativity. A vacuum is a whole spacetime, or a solution of the field equations, in which the stress–energy tensor is zero everywhere. Such a spacetime can still be curved: the Schwarzschild solution is a vacuum surrounding a mass, because the mass itself lies outside the region described. Physicists speak of vacuum solutions in the plural.
- 9In databases, to optimize a table by physically removing rows that were previously deleted.
Engineers vacuum large tables regularly to reclaim disk space.
The maintenance job vacuumed the orders table overnight.
Note
Database jargon borrowed from the household verb. When rows are deleted, they are first only marked as gone and left in place. Vacuuming removes them physically and returns the space. The verb is transitive, taking a table or a database as its object, and it forms compounds: Inside Symbian SQL (2010) describes an auto-vacuumed database, which truncates its file once pages are no longer needed.
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Origin
Borrowed from New Latin vacuum ("vacuum"), a sense of Classical Latin vacuum ("empty space"), which was a noun form of vacuus ("empty"); it is related to vacāre ("to be empty").