'proteinase' originates from the combination of the noun 'protein' and the enzyme-forming suffix '-ase' (coined from names like 'diastase'). 'protein' ultimately derives from Greek 'proteios' meaning 'primary' or 'first'.

'protein' entered English via Modern Latin 'proteina' from Greek 'proteios'; the suffix '-ase' was adopted from enzyme names such as 'diastase' in the 19th century and became a productive suffix for naming enzymes, and scientific usage combined them into 'proteinase'.

Initially it referred specifically to an enzyme acting on proteins; over time the term has remained consistent and is used generally for enzymes that hydrolyze proteins.