of, relating to, or shaped like a triangle; having three angles; triangular.
Crystallography. having threefold symmetry.

Nearby words

  1. triglyceride,
  2. triglyph,
  3. trigo,
  4. trigon,
  5. trigon.,
  6. trigonal trisoctahedron,
  7. trigonally,
  8. trigone,
  9. trigone of bladder,
  10. trigonid

Origin of trigonal

First recorded in 1560–70; trigon + -al1

Related formstrig·o·nal·ly, adverbsub·trig·o·nal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for trigonal

British Dictionary definitions for trigonal



another word for triangular (def. 1)
Also: rhombohedral relating or belonging to the crystal system characterized by three equal axes that are equally inclined and not perpendicular to each other
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

Science definitions for trigonal



Relating to a crystal having three axes of equal length intersecting at oblique angles. This crystal system is considered a subset of the hexagonal system. The mineral quartz has trigonal crystals. Also called rhombohedral See illustration at crystal.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.