The word 'triune' is a modern formation, coined in the 17th century from two classical roots to serve a specific theological need. It directly combines the Latin-derived 'tri-' (three) and '-une' (a variant of 'uni-', from Latin 'ūnus' meaning one). This construction was designed to encapsulate the paradoxical Christian doctrine of the Trinity—three distinct persons (Father, Son, Holy Spirit) existing as a single Godhead. Thus, the term's logic is purely synthetic, building an abstract concept from the literal arithmetic of its classical morphemes to describe a complex unity in plurality.

Structure: tri (three) + une (one) 'tri' is a combining form from Latin 'trēs' and Greek 'treis', meaning "three". 'une' is a variant of the combining form 'uni', from Latin 'ūnus', meaning "one".