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 One of my favorites is an untitled work that features a plushy five-point star in shades of light brown enclosed in a red pentagon that fades to pink. Roberta Smith, New York Times, "3 Art Gallery Shows to Explore From Home," 2 Apr. 2020 If this pentagon were any bigger, five-star generals would show up for work at it. Ezra Dyer, Car and Driver, "Tested: 2020 Genesis G90 Would Like Your Attention," 30 Mar. 2020 The effect is a messy storyline that feels engineered to keep season 15’s stale-back-then love pentagon going. Ariana Romero,, "Grey’s Anatomy Needs To Stop Hurting Its Very Best New Couple," 31 Jan. 2020 The pentagon is turning to crowdsourcing to come with some ideas. Kyle Mizokami, Popular Mechanics, "Are Members of the Space Force Called...Spacers?," 9 Feb. 2020 Preceding Orion are the bright autumn constellations Taurus the Bull, with the wonderful Pleiades star cluster, and Auriga, the constellation that looks like a lopsided pentagon with the bright star Capella. Mike Lynch, Twin Cities, "Skywatch: Have a holly jolly starwatching season," 1 Dec. 2019 At the crime scene Sunday night, yellow police tape formed a pentagon around the intersection of North Kimball and North Allen avenues. Alice Yin,, "Gunman kills 22-year-old man after trying to carjack him in Logan Square, police say," 23 Sep. 2019 The images that the lines create in a mandala become symbols that can include the pentagon, meaning perfection and dots that represent everything is one. Lyndi Mcnulty,, "An Eye for Art: Sharing her mandalas gives Westminster artist ‘feelings of peace’," 20 Nov. 2019 His 6-foot-5 frame towers over the 17-inch rubber pentagon at his white-cleated feet. Shayna Rubin, The Mercury News, "Three key stats: Matt Olson’s home runs, hard hits and WAR," 19 Sep. 2019

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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Time Traveler for pentagon

Time Traveler

The first known use of pentagon was in 1570

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Cite this Entry

“Pentagon.” Dictionary, Merriam-Webster, Accessed 17 May. 2021.

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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

More from Merriam-Webster on pentagon

Nglish: Translation of pentagon for Spanish Speakers

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

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