Quaternity

Part of speech: noun

Pronunciation: /kwəˈtɜː(ɹ)nɪti/

Definitions

1. A group or set consisting of four elements or parts, or the quality of being composed of four units
2. A concept denoting a collection of four distinct components or the characteristic of being organized into four parts
3. An arrangement that highlights the existence of four interconnected elements or the state of comprising four different units

Etymology: The most striking thing about "quaternity" is that its core sense was coined as a deliberate echo of a theological term. Late Latin "quaternitās" was modelled on "trīnitās" ("triad", and in Christian usage "the Trinity"), so the word was built to name a group of four in the same way that "Trinity" named three persons in the Godhead. Christian writers used it for the doctrine that there are four persons in the Godhead, a usage that passed into Middle French as "quaternité" and from there into English. The word's ancestry runs back to the Latin number four. "Quater" meant "four times", and "quaternus" ("four at a time; fourfold") was formed from it with a distributive suffix. Late Latin then added the abstract-noun suffix "-tās", giving "quaternitās" as a noun for the state of being a group of four. English borrowed the word directly through Middle French and added its own "-ity", a suffix that likewise forms abstract nouns.