'pyretogenic' originates from Greek roots: 'pyret-' from Greek 'pyretos' meaning 'fever' and suffix '-genic' from Greek 'genic' (from 'genēs') meaning 'producing' or 'generated by'.

'pyretogenic' is a modern English coinage formed from Neo-Latin/Greek elements (compare New Latin/medical formations like 'pyret- + -genic') rather than from an older Germanic or Old English word; it entered medical/technical usage in modern scientific literature.

Initially and historically it has meant 'producing or causing fever'; this core meaning has been retained in modern medical usage.