plenum

noun

1. 1

   A space that is completely filled with matter.

2. 2

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

3. 3

   A legislative meeting (especially of the Communist Party) in which all members are present.

4. 4

   An enclosed space having greater than atmospheric pressure.

5. 5

   The space above a false ceiling used for cables, ducts etc.

6. 6

   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.