Word
pentagon
Phoneticspen·ta·gon
US/ˈpɛnɪˌɡɑn/
UK/pˈɛntəɡən/
Definitions
01geometric shape
n. a flat shape that has five straight sides and five angles.
n. a polygon with five sides and five interior angles.
“The children learned how to draw a perfect pentagon in their geometry class.”
“The architect incorporated a regular pentagon into the floor plan to create a unique flow between the five main galleries.”
02U.S. military headquarters
n. the large five-sided building near Washington, D.C., where the U.S. Department of Defense is located.
n. the headquarters building of the United States Department of Defense, located in Arlington, Virginia.
“He was promoted to a new position at the Pentagon last year.”
“Security around the Pentagon was significantly increased following the announcement of the new defense protocols.”
American English
03U.S. military leadership
n. the people who lead the U.S. military and make defense decisions.
n. a metonym for the leadership and administrative authority of the United States Department of Defense.
“The Pentagon announced a new plan to support international peace efforts.”
“Political analysts spent the week debating whether the Pentagon would approve the proposed budget cuts for the next fiscal year.”
Academic · American English
Usage
Usually used with 'the' and capitalized.
Real-World Examples
“The Pentagon is currently embroiled in an ongoing war on Iran, which the US launched with Israel on February 28.” “The 2025 fiscal-year budget marked the first time debt service costs exceeded Pentagon funding.” “The Pentagon did not immediately respond to questions about this story.” Etymology
From the shape of the building.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Domain
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englishreference.com/q/pentagon