octagon

American  

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

noun

• octagons
  plural

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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Other Word Forms

Noun Inflected Forms

• octagons
  plural

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

See Examples For:

octagon octagons

There's also the question over whether McGregor will even return to the octagon, so waiting for the Irishman would come with huge risk.

From BBC ● Jul. 12, 2026

And so, as these fighters walked stone-faced to the octagon, we bore witness to the revolting spectacle of the troops saluting fighters.

From Slate ● Jun. 16, 2026

OutKick — the Fox-affiliated sports site — breathlessly covered the octagon girls’ new red, white and blue outfits, describing them as possessing “American glamour.”

From Salon ● Jun. 15, 2026

It has taken McGregor five years since his injury to return to the octagon.

From Los Angeles Times ● Jun. 12, 2026

At lunch and after school they often gathered at a wooden table in the hallway that people called the hex table, even though, as Ian pointed out, it was an octagon, not a hexagon.

From "The 57 Bus" by Dashka Slater

But borders are borders, and once Strickland has been ejected, it doesn’t take long for everyone to get back to Fan Festing at the various octagons scattered around the Ellipse.

From Slate ● Jun. 16, 2026

It's like jumping into a kaleidoscope, with constantly shifting triangles, pentagons and octagons.

From BBC ● May 25, 2025

Jay drew a simple sketch of the interlocking octagons and diamonds that would form the arched ribs of the dome, but he never made a true blueprint.

From Los Angeles Times ● Mar. 9, 2023

It didn’t cover steering, brakes, red octagons at the end of the street, what a yellow light means.

From Washington Post ● Sep. 8, 2021

I have drawn the lower figure to show how the squares which contain the octagons are obtained by means of the diagonals, 177 BD, AC, and the central line OV2.

From The Theory and Practice of Perspective by Storey, G. A. (George Adolphus)