plenum

noun

1. A space that is completely filled with matter.

   “The idea was that a thing could only move into an empty place, and that, in a plenum, there are no empty places.”

   “The key to understanding medieval interpretations of motion in hypothetically void space is to realize that medieval natural philosophers analyzed the same bodies in the void that they discussed in the plenum of their ordinary world.”

2. (figuratively)A state of fullness, a great quantity (of something).

   “He lay on the long stone slant down to the slapping waves, his denim shorts, sneakers, and socks under his head for a pillow, feeling the splendour of distance in all directions, the liquid silence, the plenum of aloneness.”

3. A legislative meeting (especially of the Communist Party) in which all members are present.
4. An enclosed space having greater than atmospheric pressure.
5. The space above a false ceiling used for cables, ducts etc.
6. A type of network cabling which satisfies a given plenum rating for the purpose of fire safety.