Trigonal
Pronunciation : Trig"o*nal
Part of Speech : a.
Definition : Defn: Having three angles, or corners; triangular; as, a trigonal stem, one having tree prominent longitudinal angles.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder