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1. Of or relating to a tetrahedron.
2. Having four faces.

tet′ra·he′dral·ly adv.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˌtɛ trəˈhi drəl)

1. pertaining to or having the form of a tetrahedron.
2. having four lateral planes in addition to the top and bottom.
tet`ra•he′dral•ly, adv.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in classic literature ?
We shall not try to give the reader an idea of that tetrahedral nose, that horseshoe mouth; that little left eye obstructed with a red, bushy, bristling eyebrow, while the right eye disappeared entirely beneath an enormous wart; of those teeth in disarray, broken here and there, like the embattled parapet of a fortress; of that callous lip, upon which one of these teeth encroached, like the tusk of an elephant; of that forked chin; and above all, of the expression spread over the whole; of that mixture of malice, amazement, and sadness.
The Molymod Shapes of Molecules Model is an educational aid designed for students with learning disabilities to teach them how to create eight models that feature examples of coordination numbers 1 to 6, including linear hydrogen chloride, linear beryllium chloride, bent water, trigonal planar, pyramidal ammonia, tetrahedral methane, trigonal bipyramidal and octahedral sulfur hexafluoride.
For the compositions under investigation, a value of Z=2.65-2.67 corresponding to x=25-27 at.% has been obtained as critical for a transition from 2D cross-linked chains arrangements to formation of 3D network of tetrahedral Ge[Se.sub.4] and pyramidal Ge[Se.sub.3] when the x value increases [5, 13].
Out of 54 spleens observed for the present study, 21 (38.88%) wedge, 12 (22.22%) triangular, 6 (11.11%) tetrahedral, 11 (20.37%) oval & 4 (7.40%) irregular shaped spleens were noted [Fig.
The AMBEO VR Mic is an Ambisonics microphone that uses four carefully selected, matched capsules in a tetrahedral arrangement.
There are two types of conventional vacancy trap sites in face-centered cubic cells: octahedral sites and tetrahedral sites.
The nature and number of coordinating ligands together with the overall coordination geometry of the system dictate the wavelengths and the intensities at which this absorption occurs [37, 38]: an intense band ([epsilon] > 300 [M.sup.-1] [cm.sup.-1]) at 625 [+ or -] 50 nm is diagnostic of a tetrahedral coordination and a weak band ([epsilon] [less than or equal to] 30 [M.sup.-1] [cm.sup.-1]) at 525 [+ or -] 50 nm reveals an octahedral complex.