octagon

American  

[ok-tuh-gon, -guhn] / ˈɒk təˌgɒn, -gən /

noun

1. a polygon having eight angles and eight sides.

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octagon British  

/ ˈɒktəɡən /

noun

1. a polygon having eight sides

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octagon Scientific  

/ ŏk′tə-gŏn′ /

1. A polygon having eight sides.

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octagon Cultural  

1. A polygon having eight sides.

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Etymology

Origin of octagon

1650–60; < Latin octagōnon < Greek oktágōnon, noun use of neuter of oktágōnos octangular; see octa-, -gon

Explanation

An octagon is a shape with eight sides. Picture a stop sign, and you'll get the idea. If your house is a strange, roundish shape with eight walls, it's an octagon, and if your medal for being the most improved bowler in your league has a shape with eight equal sides, it's also an octagon. You'll come across the word most often in geometry class, where you'll also learn that an octagon's eight interior angles always add up to 1080 degrees. The Greek root is oktagononos, "eight-angled," from okto, "eight," and gonia, "angle."

Example Sentences

Bouts take place in an eight-sided ring -- dubbed "The Octagon" -- bounded by a chainlink fence.

From Barron's • Mar. 8, 2026

He retired from Octagon in 2003 and later formed his own small firm, Altis Marketing, providing advice to corporate sponsors.

From The Wall Street Journal • Jan. 21, 2026

Grande’s Celine Dion promised to see you in The Octagon.

From Los Angeles Times • Oct. 13, 2024

He originally hails from Radcliffe, seven miles north, and recalls how his first job as an usher at the Bolton Octagon theatre led to his career directing for stage, screen and stadium.

From BBC • Oct. 17, 2023

As those conversations took place, the one thing that stood out for my parents and me was the personal connection I felt with the agent I ultimately chose, Janey Miller from Octagon.

From "Courage to Soar" by Simone Biles