'apathogenic' originates from Greek, specifically the prefix 'a-' meaning 'not' combined with 'pathogenic' (from Greek 'pathos' meaning 'suffering, disease' and the element '-genic' from Greek 'genēs' meaning 'born' or 'producing').

'pathogenic' entered English in the 19th century (via Modern Latin/French influenced by Greek 'pathos' + '-genic'); 'apathogenic' was later formed in modern English by adding the Greek privative prefix 'a-' to 'pathogenic' to indicate absence of disease-causing ability.

Initially it meant 'not producing disease' and this core meaning has remained stable in scientific usage.