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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
UCPS 6th Grade Roots List #6
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Geometry (Base List)
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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:
During his time out of the octagon, he observed how the division changed.
From Los Angeles Times ● Sep. 19, 2026
Despite Makhachev's record, Machado Garry displayed typical confidence as he made his walkout, before greeting his wife and draping an Ireland flag around him prior to entering the octagon.
From BBC ● Aug. 16, 2026
Troop bands playing music onstage, troops putting on military combatives exhibitions in the octagon, troops sitting, uniformed and visible, beneath the Claw to watch the spectacle in person.
From Slate ● Jun. 16, 2026
There is a 600-ton octagon still sitting on the South Lawn.
From Salon ● Jun. 15, 2026
The octagon P1 P2 P3 P4 P5 P6 P7 P8 is inscribed in a circle, with the vertices around the circumference in the given order.
From "The Miscalculations of Lightning Girl" by Stacy McAnulty
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
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
The octagons and squares in the dining room rug exuded a strong sense of character, as did the nearby studio space.
From New York Times ● Oct. 6, 2017
In Scott’s enumeration the vaults of octagons and irregular compartments, and such varieties as the one called sexpartite, find a place; here they have been intentionally excluded.
From Architecture Gothic and Renaissance by T. Roger (Thomas Roger) Smith
Random Word
Spin the wheel and learn a new word!
Get a wordDefinitions 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.
