'immunogenic' originates from Modern Latin/Neo-Latin and Greek elements, specifically the Latin word 'immunis' and the Greek root 'gen-' (from 'genos'), where 'immunis' meant 'exempt' and 'gen-' meant 'beget/produce'.

'immunogenic' formed in scientific/medical English by combining 'immune' (from Latin 'immunis' via earlier English usage) with the Greek-derived suffix '-genic' (meaning 'producing'), appearing in biomedical literature in the 19th–20th centuries to denote something that produces immunity.

Initially formed to mean 'producing immunity' or 'causing an immune response'; over time it has been used broadly to describe any substance or agent capable of provoking an immune response (its current meaning).