arius

Arius or arius is a term that mostly appears as a proper name in historical and linguistic contexts. In Latin, -arius is a productive suffix that forms nouns and adjectives indicating relation or occupation, producing words such as librarius (librarian) or consiliarius (counselor). The lowercase form arius is uncommon outside linguistic examples or when used as part of a longer term derived from Latin.

The most well-known bearer of the name is Arius of Alexandria (circa 256–336 CE). He was a Christian priest whose teachings on the nature of the Son and the Trinity gave rise to Arianism, a major theological controversy in the early church. His views were condemned at the Council of Nicaea in 325, leading to a lasting split within early Christianity. The term "Arian" derives from his name.

In modern usage, Arius is encountered primarily as a given name or surname in various cultures, and in academic discussions the word arius may appear when illustrating Latin naming patterns or etymology. The uncapitalized form arius does not designate a distinct concept.

There is not a single topic or concept universally associated with arius, but readers may encounter it in discussions of ancient theology, onomastics, or Latin linguistics. For clarity, it is often treated under Arius (disambiguation) or explained as the Latin suffix -arius when describing word formation.