trihedron [trahy-hee-druh n] WORD ORIGIN noun, plural tri·he·drons, tri·he·dra [trahy-hee-druh] /traɪˈhi drə/. Geometry. the figure determined by three planes meeting in a point.
Also. Origin of trihedron First recorded in 1820–30; + Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019 British Dictionary definitions for trihedron trihedron noun plural -drons or -dra (-drə) a figure determined by the intersection of three planes 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