'sepsis' originates from Greek, specifically the word 'sēpsis' (σηψις), where the root 'sēp-' meant 'putrefaction' or 'to rot'.

'sepsis' entered English via Latin/Medieval Latin (Latin: 'sepsis'), borrowed from Greek 'sēpsis' (σηψις); the term was used in medical Latin and later adopted into English medical vocabulary as 'sepsis'.

Initially it referred primarily to 'putrefaction' or decaying (literal rotting), but over time the meaning shifted to the clinical sense of a dangerous systemic response to infection (modern medical usage).