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

The Communist Party plenum will debate China's next Five-Year Plan, the 15, setting important markers for the coming years. —Deirdre Kirsten Tatlow, MSNBC Newsweek, 21 Oct. 2025

About a dozen seats are expected to be filled by alternate members at this plenum. —Simone McCarthy, CNN Money, 20 Oct. 2025

The Israeli leader rejected such charges in his speech, albeit to a near-empty plenum. —Laura Kelly, The Hill, 26 Sep. 2025

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

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