'avirulence' originates from Latin/Neo-Latin formation, specifically built from the negative prefix 'a-' (meaning 'not') combined with 'virulentia' (from Latin 'virulentus'), where 'virulentus' derived from 'virus' meant 'poison' or 'venom'.

'avirulence' developed as a Neo-Latin/technical formation (a- + virulentia) used in scientific contexts; this formation entered English usage in the 19th–20th century and stabilized as the noun 'avirulence' in modern scientific writing.

Initially it referred to the literal absence or reduction of 'poisonousness' or harmful potency; over time it has remained specialized in meaning and is used to denote absence or reduction of pathogenicity or harmful virulence.