from The American Heritage® Dictionary of the English Language, 5th Edition.
- adjective Rhombohedral.
from The Century Dictionary.
- Pertaining to a trigon; having the form of a trigon; triangular.
- In entomology, triangular in cross-section; having three long edges; trihedral; prismatic: as, trigonal antennæ; trigonal joints.
- In botany, same as
- In anatomy, noting a triangular space at the base of the bladder. See
- noun In anatomy, the triangular space at the base of the bladder; the trigonum.
from the GNU version of the Collaborative International Dictionary of English.
- adjective Having three angles, or corners; triangular.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adjective having threefold symmetry
from The American Heritage® Dictionary of the English Language, 4th Edition
Both have identical major ion chemistry CaCO3 but different structures: calcite is trigonal whilst aragonite is orthorhombic.
-- Here there is rotation of one portion with respect to the other through 180° about the principal (trigonal) axis, which is perpendicular to the plane c (111); or the same result may be obtained by reflection across this plane.
Horns very large, depressed and sub-trigonal at the base, attached to the highest line of the frontals, inclining upwards and backwards, conical towards the tip and bending upwards; muffle large, square.
The horns are trigonal, laterally compressed and knotted on the upper edge.
[VENUS LATILIRATA] Shell sub-trigonal, thick and ponderous for its size; ribs fine, concentric, and very thick; irregularly stirate, crenulate upon the lower margin; umbo slightly flattened.
"The general form is trigonal, or wedge form, valves closed, front produced, posterior short; margins usually crenulated; hinge teeth 2 -- 2; laterals 1 -- 1 in each valve; pallial sinus deep."
Moreover, some evidence suggests a cardiomyogenic differentiation capacity of MPCs, revealing the capacity to generate quadri - or trigonal cells positive for α-actinin and troponin I (data not shown).
Pure corundum is a colorless, trigonal crystal with a hardness between that of emerald and diamond.
The newest - and possibly the best - blue pigment in world history was born, due to manganese ions being structured in an unusual "trigonal bipyramidal coordination" in the presence of extreme heat.
Hornberg A, Tunemalm AK, Ekstrom F (2007) Crystal structures of acetylcholinesterase in complex with organophosphorus compounds suggest that the acyl pocket modulates the aging reaction by precluding the formation of the trigonal bipyramidal transition state.