'antipapacy' originates from Greek 'anti-' and Latin/Old French elements forming 'papacy' — specifically Greek 'antí' meaning 'against' and Late Latin 'pāpātus' (via Old French 'papacie') where 'papa'/'pappas' meant 'father'.

'antipapacy' was formed in English by combining the prefix 'anti-' (Greek) with the noun 'papacy' (from Late Latin 'pāpātus' via Old French 'papacie'); the parts came together in post-medieval English usage to name the phenomenon of opposition to the papal office.

Initially used to denote specifically the office or claim of an antipope, the term has also come to be used more broadly for movements or periods characterized by organized opposition to papal authority.