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

Such fanciful rumors are common in authoritarian systems, especially in the lead-up to major political events—such as the Chinese Communist Party’s fourth plenum, which took place in October, and whose outcomes are expected to set the country’s developmental direction for the next five years. —Deng Yuwen, Foreign Affairs, 14 Nov. 2025

Boosting consumer spending and livelihoods gets little more than lip service in the communiqué that followed the plenum at which the five-year plan was mapped out. —Shaoyu Yuan, The Conversation, 5 Nov. 2025

Nearly one in five Central Committee members missed the latest plenum under a political cloud, a record in China’s post-Mao era. —Neil Thomas, Time, 29 Oct. 2025

The 15th Five-Year Plan, which was announced after the fourth plenum of the 20th Communist Party Congress in Beijing last week, is viewed as a continuation of policy efforts announced last year and does not signal a paradigm shift. —Denni Hu, Footwear News, 29 Oct. 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