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Synonyms

octagonal

American  
[ok-tag-uh-nl] / ɒkˈtæg ə nl /

adjective

  1. having eight angles and eight sides.


octagonal British  
/ ɒkˈtæɡənəl /

adjective

  1. having eight sides and eight angles

  2. of or relating to an octagon

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of octagonal

1565–75; octagon + -al 1, replacing earlier octogonal < New Latin octōgōnālis, equivalent to octō- octo- + Greek gōn ( ía ) angle + -ālis -al 1

Explanation

Anything that's octagonal has eight sides and eight angles. A stop sign has an octagonal shape, and so may your trampoline You can also call something that's octagonal an octagon. Octagonal buildings may be unusual, but you can find examples of them around the world — there are many churches and cathedrals with octagonal sections, for example. Both octagonal and octagon come from the Greek oktagononos, "eight-angled," from the roots okto, "eight," and gonia, "angle."

Keep Reading on Vocabulary.com

Vocabulary lists containing octagonal

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:

The temporary arena that has been under construction is slated to feature an octagonal cage for the fights at its center, and it’s expected to fit about 4,000 guests.

From MarketWatch May 29, 2026

Original plans called for an octagonal building with a grand piano.

From The Wall Street Journal Dec. 14, 2025

There’s dark woodwork, octagonal pillars, curlicues of ironwork in the old-fashioned windows, carved details of garlands and flowers and urns.

From Seattle Times Feb. 15, 2024

Some of the findings are "unique" for South America, he explains, pointing to the octagonal and rectangular platforms arranged together.

From BBC Jan. 11, 2024

Built of white limestone and pink Aswan granite, the Pharos had a tripartite structure based on a vaguely Pythagorean geometric theme, with a square-sided base, octagonal middle, and circular upper stage.

From "Circumference" by Nicholas Nicastro

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