'anaerobe' originates from French, specifically the word 'anaérobie', where 'an-' meant 'without' and 'aérobie' referred to 'aerobic' (relating to oxygen).

'anaérobie' was adopted into English as 'anaerobe', and the plural form 'anaerobies' is used to refer to multiple such organisms.

Initially, it meant 'an organism living without oxygen', and this meaning has remained the same in modern usage.