'fandom' originates from English, formed from 'fan' (short for 'fanatic') + the suffix '-dom' (from Old English 'dōm' meaning 'state' or 'judgment'), where 'fan' originally meant 'enthusiast' and '-dom' meant 'state or domain'.

'fan' is a shortening of 'fanatic', from Latin/Greek roots ('phanatikos' via Late Latin/French) meaning 'inspired by a god' and later 'excessive enthusiasm'; the suffix '-dom' comes from Old English 'dōm' meaning 'judgment, statute' that evolved to mean 'state, condition, domain'; these elements combined in modern English to form 'fandom' in the late 19th to early 20th century to mean the community or state of fans.

Initially it referred to the state of being a fan or fanaticism; over time it has come to commonly mean the community or organized group of fans around a particular subject.