octagon
Americannoun
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.
In the center is the so-called "Octagon", the eight-sided cage where 14 UFC fighters will battle it out in front of Trump in the unprecedented event on Sunday night.
From Barron's • Jun. 11, 2026
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
When Aunt Loma happened along, carrying the baby, she stared at Miss Love a minute, then flounced into the store and came over where I stood putting bars of Octagon soap on a shelf.
From "Cold Sassy Tree" by Olive Ann Burns
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.
