Added 9 October 2026 arius noun Categories: PeopleAnimalsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about arius at Wordnik → Where our words come from → A Greek who was a Christian theologian active in Alexandria and who was declared a heretic for his doctrines about God (which came to be known as Arianism) (256?-336). Type genus of the Ariidae: sea catfishes. Related Words: arrianarianneariannaarianaariaharianearistarchusaetiusaurelianarieariya Back to today's word