octagon
Americannoun
-
octagons
plural
noun
Other Word Forms
Noun Inflected Forms
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."
Vocabulary lists containing octagon
Geometry - Introductory
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UCPS 6th Grade Roots List #6
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Geometry (Base List)
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Makhachev is not as aggressive in the octagon as Nurmagomedov but is a more well-rounded striker, while his only defeat came against Adriano Martins in 2015.
From BBC ● Aug. 13, 2026
There is a 600-ton octagon still sitting on the South Lawn.
From Salon ● Jun. 15, 2026
The centrepiece is the "Claw" - a 92ft high metal structure that looms over the octagon and many of the seats.
From BBC ● Jun. 14, 2026
Khabib Nurmagomedov, one of the best grapplers to ever set foot in the octagon, was set to compete for the lightweight belt.
From Slate ● Jun. 14, 2026
It was a perfect octagon, the eight sides joined at the corners by rippling seams of silver.
From "Tristan Strong Punches a Hole in the Sky" by Kwame Mbalia
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
"There are other much more exact modes of making octagons than this, but I cannot stop to describe them here."
From The Atlantic Monthly, Volume 05, No. 28, February, 1860 by Various
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
