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