IPA: /ˈtrɪɡənəli/
KK: /ˈtrɪgənəli/
In a way that relates to or resembles a triangle or trigonal shape.
The crystals were arranged trigonally to maximize their stability.
Trigonally → It is formed from "tri-" (meaning three) and "gon" (from Greek "gōnia", meaning angle) and the suffix "-ally" (meaning in a manner). The word "trigonally" refers to something that is related to or shaped like a triangle, or in a manner pertaining to three angles.
Think of 'tri-' meaning three and 'gon' referring to angles, so when something is described as trigonally, it relates to three angles, like a triangle.