trigonal

[ trig-uh-nl ]

adjective

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

trigonal

/ ˈtrɪɡənəl /

adjective

1. another word for triangular
2. Alsorhombohedral relating or belonging to the crystal system characterized by three equal axes that are equally inclined and not perpendicular to each other

trigonal

/ trī-gō′nəl /

1. 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.
2. Also called rhombohedral
3. See illustration at crystal

Other Words From

• trigo·nal·ly adverb
• sub·trigo·nal adjective

Word History and Origins

Origin of trigonal¹

First recorded in 1560–70; trigon + -al ¹

Example Sentences

Orifice either large and rounded-trigonal, or small and oval, either entire or less frequently toothed.

From Project Gutenberg

Parietes ribbed, mottled purplish-red; orifice broad, trigonal, hardly toothed.

From Project Gutenberg

The horns are trigonal, laterally compressed and knotted on the upper edge.

From Project Gutenberg

When the whorls are angulated, a trigonal aperture is the result, as in many species of Trochus.

From Project Gutenberg

Mactracea (plates, fig. 77 to 88), the cartilage placed in a trigonal pit, with a small external ligament.

From Project Gutenberg

Related Words

• trilateral