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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. 2017.
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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
  • The Font is often, following ancient custom, octagonal in form.

    The Worship of the Church Jacob A. Regester
  • The piers are octagonal, with many shafts, the capitals enriched with foliage of Early English type.

  • This summer-house or Temple, as it has come to be called, is an octagonal structure.

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

  • She had just finished cleaning those in the octagonal dining-room.

    Old Valentines Munson Aldrich Havens
  • The font is octagonal, and has painted shields of arms in its upper panels.

  • octagonal, lofty, yet narrow, you saw at once that it formed the interior of a turret.

    Rookwood William Harrison Ainsworth
  • 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
  • Over the octagonal window, too, such draperies fell in stately lines.

    Within the Law Marvin Dana
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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