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[ok-tag-uh-nl] /ɒkˈtæg ə nl/
having eight angles and eight sides.
Origin of octagonal
1565-75; octagon + -al1, replacing earlier octogonal < New Latin octōgōnālis, equivalent to octō- octo- + Greek gōn(ía) angle + -ālis -al1
Related forms
octagonally, adverb Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for octagonal
Historical Examples
  • And I went into the octagonal room, and sat down near the window and leaned my forehead against the glass.

    The Romance of His Life Mary Cholmondeley
  • Over the octagonal window, too, such draperies fell in stately lines.

    Within the Law Marvin Dana
  • The piers are octagonal, with many shafts, the capitals enriched with foliage of Early English type.

  • He sprang to the octagonal window, even as Dick took possession of the pistol.

    Within the Law Marvin Dana
  • There are groining-shafts in the angles of the octagon, and an octagonal dome or vault, with ribs at the angles.

  • The drum dome is octagonal, with eight ribs and as many windows.

    Byzantine Churches in Constantinople Alexander Van Millingen
  • The font is octagonal, and has painted shields of arms in its upper panels.

  • It was octagonal in form, and was bordered all around with stone.

    Rollo in Paris Jacob Abbott
  • The descent to this low battery was by a slope ending in an octagonal hall whose vaults rested on four great cylindrical pillars.

    Annals of a Fortress E. Viollet-le-Duc
  • The octagonal story does not harmonize with the lower portion.

    Ely Cathedral Anonymous
British Dictionary definitions for octagonal


having eight sides and eight angles
of or relating to an octagon
Derived Forms
octagonally, adverb
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
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Word Origin and History for octagonal

1570s, from octagon + -al (1).

Online Etymology Dictionary, © 2010 Douglas Harper
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octagonal in Science
A polygon having eight sides.

octagonal adjective (ŏk-tāg'ə-nəl)
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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