noun (1)
pen·​ta·​gon | \ ˈpen-tə-ˌgän How to pronounce pentagon (audio) \

Definition of pentagon

 (Entry 1 of 2)

: a polygon of five angles and five sides


noun (2)

Definition of Pentagon (Entry 2 of 2)

: the U.S. military leadership

Examples of pentagon in a Sentence

Noun (1)

The general attended a meeting at the Pentagon. There was disagreement between the President and the Pentagon over the new military budget.

Recent Examples on the Web: Noun

In the 1970s, Marjorie Rice, a homemaker with no mathematical background, ran across a Scientific American column about pentagons that tile the plane. Quanta Magazine, "Decades-Old Graph Problem Yields to Amateur Mathematician," 17 Apr. 2018 Feeling comfortable Previous SlideNext Slide On the outside, the MDX Sport Hybrid looks a lot like its conventional-engine counterpart, including its diamond-pentagon grille along with LED headlamps and fog lights. Eric Bangeman, Ars Technica, "Love the hardware, hate the UI: The Acura MDX Sport Hybrid," 13 Dec. 2018 The sets on sale comes with colorful squares, triangles, and pentagons that can be pieced together to build 2-D or 3-D patterns. Lindsey Murray, Good Housekeeping, "Those Super-Expensive Magformers Are 50% Off on Amazon Right Now," 9 Aug. 2018 Joining me for insight and analysis are NBC News national political reporter Carol Lee, New York Times pentagon correspondent Helene Cooper, Republican strategist Al Cardenas and New York Times columnist Bret Stephens. NBC News, "Meet the Press - June 17, 2018," 17 June 2018 Sides denote privilege, with hexagons trumping pentagons, for instance. John J. Miller, WSJ, "A Multidimensional Religious Story," 8 June 2018 The black and white pentagon panels of that product, the Telstar Elust, became synonymous with the sport. Kevin Baxter,, "A closer look at the technology inside the 2018 World Cup soccer ball," 21 May 2018 In the 1970s, Marjorie Rice, a homemaker with no mathematical background, ran across a Scientific American column about pentagons that tile the plane. Evelyn Lamb, WIRED, "An Anti-Aging Pundit Solves a Decades-Old Math Problem," 30 Apr. 2018 Kind of a pentagon or home plate, with straight sides, a meandering river boundary below, and a partly straight top with a friendly bite mark out of it on the northeast side from Lake Erie. Andrew J. Tobias,, "Parody Twitter accounts are increasingly a semi-official part of political campaigns," 27 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pentagon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of pentagon

Noun (1)

1570, in the meaning defined above

Noun (2)

1945, in the meaning defined above

History and Etymology for pentagon

Noun (1)

Greek pentagōnon, from neuter of pentagōnos pentagonal, from penta- + gōnia angle — more at -gon

Noun (2)

the Pentagon building, headquarters of the Department of Defense

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Statistics for pentagon

Last Updated

14 Jul 2019

Look-up Popularity

Time Traveler for pentagon

The first known use of pentagon was in 1570

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English Language Learners Definition of pentagon

mathematics : a flat shape that has five sides and five corners
: the building in Washington, D.C., that is the headquarters of the U.S. Department of Defense
: the leaders of the U.S. military


pen·​ta·​gon | \ ˈpen-tə-ˌgän How to pronounce pentagon (audio) \

Kids Definition of pentagon

: a flat geometric figure having five angles and five sides

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More from Merriam-Webster on pentagon

Rhyming Dictionary: Words that rhyme with pentagon

Spanish Central: Translation of pentagon

Nglish: Translation of pentagon for Spanish Speakers

Britannica English: Translation of pentagon for Arabic Speakers Encyclopedia article about pentagon

Comments on pentagon

What made you want to look up pentagon? Please tell us where you read or heard it (including the quote, if possible).


appealing forcibly to the mind or reason

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