'pepsin' originates from New Latin, ultimately from Greek, specifically the word 'pepsis' (Greek: πέψις), where the root 'peptein' meant 'to digest' or 'to cook'.

'pepsin' developed from Greek 'pepsis' (meaning 'digestion') into New Latin/Modern scientific usage as 'pepsin' (coined in the 19th century when the enzyme was identified), and then entered English as the name for the specific digestive enzyme.

Initially related to the general idea of 'digestion' (process), it evolved into the modern specialized meaning referring to a specific stomach enzyme that digests proteins.