Vacuum Vac"u*um, n.; pl. E. {Vacuums}, L. {Vacua}. [L., fr. vacuus empty. See {Vacuous}.] 1. (Physics) A space entirely devoid of matter (called also, by way of distinction, absolute vacuum); hence, in a more general sense, a space, as the interior of a closed vessel, which has been exhausted to a high or the highest degree by an air pump or other artificial means; as, water boils at a reduced temperature in a vacuum. [1913 Webster]

2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.; as, a vacuum of 26 inches of mercury, or 13 pounds per square inch. [1913 Webster]

{Vacuum brake}, a kind of continuous brake operated by exhausting the air from some appliance under each car, and so causing the pressure of the atmosphere to apply the brakes.

{Vacuum pan} (Technol.), a kind of large closed metallic retort used in sugar making for boiling down sirup. It is so connected with an exhausting apparatus that a partial vacuum is formed within. This allows the evaporation and concentration to take place at a lower atmospheric pressure and hence also at a lower temperature, which largely obviates the danger of burning the sugar, and shortens the process.

{Vacuum pump}. Same as {Pulsometer}, 1.

{Vacuum tube} (Phys.), a glass tube provided with platinum electrodes and exhausted, for the passage of the electrical discharge; a Geissler tube.

{Vacuum valve}, a safety valve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, in order to prevent collapse.

{Torricellian vacuum}. See under {Torricellian}. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Vacua — (Vacca), Fluß an der Westküste Hispaniens; j. Vouga …   Pierer's Universal-Lexikon

  • vacua — pl of VACUUM …   Medical dictionary

  • VACUA — vide Vacca …   Hofmann J. Lexicon universale

  • vacua — [vak′yo͞o ə] n. alt. pl. of VACUUM …   English World dictionary

  • vacua — /vak yooh euh/, n. a pl. of vacuum. * * * …   Universalium

  • vacua — évacua …   Dictionnaire des rimes

  • vacua — vac·u·um || vækjÊŠÉ™m n. void, emptiness, vacuity; space that is empty of matter; electrical device which cleans surfaces by creating air suction v. clean with a vacuum cleaner, operate a device for cleaning carpets and floors by air suction …   English contemporary dictionary

  • vacua — plural form of vacuum …   English new terms dictionary

  • vacua — /ˈvækjuə/ (say vakyoohuh) plural noun a plural of vacuum …   Australian English dictionary

  • vacua — pl. of VACUUM …   Useful english dictionary

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