plenum

noun

ple·​num ˈple-nəm  ˈplē- 

1

a

: a space or all space every part of which is full of matter

b

: an air-filled space in a structure

especially : one that receives air from a blower for distribution (as in a ventilation system)

2

: a general assembly of all members especially of a legislative body

3

: the quality or state of being full

Examples of plenum in a Sentence

Recent Examples on the Web

And it's beautifully sculpted, as the mid-engine is designed to always be visible from both inside and outside the car – the plenum being the centerpiece; a perfect balance of aesthetics and intake performance. —New Atlas, 28 Apr. 2025

Of course, that nothing much will change was largely self-evident by the fact that this NPC follows on the heels of last July’s third CCP plenum, where long-term goals were laid out: bolstering party-state capitalism, countering U.S. containment, boosting innovation, and entrenching loyalty to Xi. —Charlie Campbell, TIME, 5 Mar. 2025

Chemical Smell Chemical scents can be produced when the heat exchanger is not properly cycling heat from the combustion chamber into the plenum. —Timothy Dale, Better Homes & Gardens, 10 Jan. 2025

At the recent party plenum, Xi’s status within the party was elevated yet again, with the official rewriting of China’s communist history to position him as the country’s modern savior, laying the foundation for a certain third term as party leader after next fall’s 20th Party Congress. —Jude Blanchette, Foreign Affairs, 23 Nov. 2021

Word History

Etymology

borrowed from Latin plēnum, noun derivative from neuter of plēnus "full"; (sense 1a) after its use in the Lucullus book of Cicero's Academica to denote a space completely filled with matter (distinguished from ināne or vacuum "empty space"); (sense 2) apparently first from its use in Sweden in the eighteenth century to refer to a meeting of all members of the Riksdag — more at full entry 1

First Known Use

1678, in the meaning defined at sense 1a

Rhymes for plenum

• denim
• venom
• imipenem