'nonanthropogenic' originates from modern English, specifically formed from the negative prefix 'non-' (from Latin 'non') and 'anthropogenic' (from Greek 'anthropos' + '-genic'), where 'non-' meant 'not' and 'anthropogenic' meant 'produced or caused by humans'.

'anthropogenic' derives from Greek 'anthropos' ('human') + '-genic' ('producing/causing') and entered English as a scientific term in the 19th–20th centuries; the negative prefix 'non-' was later attached in modern English to form 'nonanthropogenic' to denote absence of human causation.

Initially it meant 'not produced by humans,' and this core meaning has remained stable, used mainly to distinguish natural processes from human-caused (anthropogenic) ones.