'bahai' originates from Arabic and Persian, specifically the Arabic word 'bahā' (بهاء) meaning 'splendor' or 'glory', combined with the Persian adjectival/relational suffix '-í' which indicates 'related to' or 'belonging to'.

'bahai' changed from the Persian/Arabic title form 'Bahā'ī' (used to denote association with 'Bahā' as in 'Bahā'ī') and eventually entered English as the modern term 'bahai' (often written 'Bahá'í').

Initially the root 'bahā' meant 'splendor' or 'glory'; over time the combined form came to denote a follower or anything relating to the Bahá'í Faith rather than the original abstract meaning.