from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. An assembly or meeting with all members present.
  • n. A condition, space, or enclosure in which air or other gas is at a pressure greater than that of the outside atmosphere.
  • n. The condition of being full; fullness.
  • n. A space completely filled with matter.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A space that is completely filled with matter.
  • n. A state of fullness, a great quantity (of something).
  • n. A legislative meeting (especially of the Communist Party) in which all members are present.
  • n. An enclosed space having greater than atmospheric pressure.
  • n. The space above a false ceiling used for cables, ducts etc.
  • n. A type of network cabling which satisfies plenum-ratings issued by the National Electrical Code. These cables are safer in case of a fire, producing less smoke and fumes.

from the GNU version of the Collaborative International Dictionary of English

  • n. That state in which every part of space is supposed to be full of matter; -- opposed to vacuum.
  • n. A condition, as in an occupied room, in which the pressure of the air is greater than that of the outside atmosphere.

from The Century Dictionary and Cyclopedia

  • n. The fullness of matter in space: the opposite of vacuum: also used to denote fullness in general.
  • n. A quantity of a gaseous body in an inclosed space greater than would remain there under normal atmospheric pressure.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an enclosed space in which the air pressure is higher than outside
  • n. a meeting of a legislative body at which all members are present


Latin plēnum (spatium), full (space), neuter of plēnus.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin plēnum, noun use of neuter of plēnus ("full"). Influenced by Russian пленум (plénum, "plenary session"), from the same Latin source. (Wiktionary)


  • But it is more usual to employ what is called the plenum process, in which air under high pressure is pumped into the caisson and expels the water, as in a diving bell.

    Scientific American Supplement, No. 417, December 29, 1883

  • The air runs through a massive bank of modular filters to remove dust and other contaminants before it circulates in a massive cavity, called a plenum, below its data center halls.

    Latest from Computerworld

  • The flow typically proceeds from the throttle body into a chamber called the plenum, which in turn feeds individual tubes, called runners, leading to each intake port.

    Automotive News Blog at - Car News Resource

  • A motorized rolling screen integrated in a plenum is the ultimate solution to transform a living room in a stunning Home Theater.

    HiddenWires News

  • Here is life -- yours and mine -- a kind of plenum in vacuo.

    The Return

  • Space, in Descartes 'view, is a' 'plenum' 'occupied by an ether, which, imperceptible to the senses, is capable of transmitting forces on material bodies immersed in it.

    Citizendium, the Citizens' Compendium - Recent changes [en]

  • '' plenum '' occupied by an ether, which, imperceptible to the senses, is capable of transmitting forces on material bodies immersed in it.

    Citizendium, the Citizens' Compendium - Recent changes [en]

  • Second, the plenum gave more latitude to Chinese peasants to break free from the system of collective farms and to cultivate crops on individual plots through “side-occupations,” such as growing fruit and vegetables and raising livestock.7 Finally, the plenum made a nod in the direction of the need for a more independent judicial system to arbitrate the kind of disputes that would arise in a “new world of local commercial initiatives.”

    Zero-Sum Future

  • Crucially, the plenum recommended that authority should be “shifted from the leadership to the lower levels.”

    Zero-Sum Future

  • The plenum officially adopted the policy of “socialist modernization.”

    Zero-Sum Future


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  • Their memories clog me like arterial fur. I'm full, I said to Harley. I have achieved a fucking plenum. From "The Last Werewolf" by Glen Duncan.

    March 1, 2012

  • See citation on bombinate.

    March 29, 2008