ple·​na·​ry ˈple-nə-rē How to pronounce plenary (audio)
ˈplē- How to pronounce plenary (audio)
: complete in every respect : absolute, unqualified
plenary power
: fully attended or constituted by all entitled to be present
a plenary session

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In the 14th century, the monk Robert of Brunne described a situation in which all the knights of King Arthur's Round Table were present at court by writing, "When Arthures court was plener, and alle were comen, fer and ner.…" For many years, plener (also spelled plenar) served English well for both senses that we reserve for plenary today. But we'd borrowed plener from Anglo-French, and, although the French had relied on Latin plenus ("full") for their word, the revival of interest in the Classics during the English Renaissance led scholars to prefer purer Latin origins. In the 15th century, English speakers turned to Late Latin plenarius and came up with plenary. (Plenarius also comes from plenus, which is the source of our plenty and replenish as well.)

Choose the Right Synonym for plenary

full, complete, plenary, replete mean containing all that is wanted or needed or possible.

full implies the presence or inclusion of everything that is wanted or required by something or that can be held, contained, or attained by it.

a full schedule

complete applies when all that is needed is present.

a complete picture of the situation

plenary adds to complete the implication of fullness without qualification.

given plenary power

replete implies being filled to the brim or to satiety.

replete with delightful details

Examples of plenary in a Sentence

A plenary meeting of the 500 members was held last summer. plenary sessions of the legislature
Recent Examples on the Web It was agreed upon exactly eight years ago on Dec. 12 to a standing ovation at the plenary. Sibi Arasu, Fortune, 12 Dec. 2023 In a short speech before the plenary, Alswaha ran through some key issues facing the IGF, including generative artificial intelligence and the digital divide. Justin Ling, WIRED, 11 Oct. 2023 The conference's plenary sessions are being livestreamed on YouTube. Eric Berger, Ars Technica, 4 Oct. 2023 For example, Kelleher points out in her plenary that high-performance computing demands a large amount of cache memory per processor core, but chipmaker’s ability to shrink SRAM is not proceeding at the same pace as the scaling down of logic. IEEE Spectrum, 5 Dec. 2022 Hours later, outside the plenary session, small island nations and European nations along with Colombia, held hands and hugged in an emotional show of support for greater ambition. Seth Borenstein, David Keyton, Jamey Keaten and Sibi Arasu The Associated Press,, 14 Dec. 2023 Delegates at a plenary session on the final day of the United Nations COP28 climate conference. Rochelle Toplensky, WSJ, 14 Dec. 2023 The consequences of 1898 have been enduring, particularly for Puerto Rico and Guam, which remain unincorporated territories of the U.S. under the plenary power of Congress, a decision sustained by the Supreme Court in the Insular Cases of 1901. Taína Caragol, Smithsonian Magazine, 8 Aug. 2023 In 2016’s Puerto Rico v. Sanchez Valle, the U.S. Supreme Court held that Puerto Rico has no real political sovereignty and that whatever authority its government appears to have actually emanates from the plenary powers of Congress. Alberto C. Medina, The New Republic, 24 July 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'plenary.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English plenarie, borrowed from Late Latin plēnārius, from Latin plēnus "full" + -ārius -ary entry 2 — more at full entry 1

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of plenary was in the 15th century


Dictionary Entries Near plenary

Cite this Entry

“Plenary.” Dictionary, Merriam-Webster, Accessed 24 Feb. 2024.

Kids Definition


ple·​na·​ry ˈplē-nə-rē How to pronounce plenary (audio) ˈplen-ə- How to pronounce plenary (audio)
: complete in all ways : full
plenary powers
: including all who have a right to attend
a plenary session of an assembly

Legal Definition


ple·​na·​ry ˈplē-nə-rē, ˈple- How to pronounce plenary (audio)
: full and complete in every respect: as
: absolute sense 1
plenary power
: fully attended or constituted
a plenary session of the legislature
: including all steps in due order
a plenary proceeding
compare summary

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