'arianism' originates from Modern English, specifically from the proper name 'Arius' combined with the suffix '-ism' (from Greek/Late Latin '-ismos'/'-ismus'), where 'Arius' referred to the 4th-century presbyter Arius and '-ismos' meant 'practice, system, or sect'.

'arianism' changed from Medieval Latin 'arianismus' (and Middle English 'arianisme') and eventually became the modern English word 'arianism'.

Initially, it meant 'the teachings or followers of Arius', but over time it evolved into its current meaning of 'the doctrine that the Son is distinct from and subordinate to the Father' (a Christological position historically labeled as heresy by orthodox Christianity).