• synonyms


[trahy-hee-druh l]
adjective Geometry.
  1. having, or formed by, three planes meeting in a point: a trihedral angle.
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  1. a trihedron.
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Origin of trihedral

First recorded in 1780–90; tri- + -hedral
Related formssub·tri·he·dral, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for trihedral

Historical Examples

  • The angle between two planes is termed dihedral, between three trihedral, between any number more than three polyhedral.

    Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1


  • A triangle and a trihedral angle are therefore reciprocal figures.

British Dictionary definitions for trihedral


  1. having or formed by three plane faces meeting at a point
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  1. a figure formed by the intersection of three lines in different planes
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Word Origin

C18: from tri- + Greek hedra base, seat + -al 1
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