'beta-haemolytic' originates from Greek and New Latin: 'beta' originates from Greek 'beta' (the second letter of the Greek alphabet), where 'beta' meant 'second'; 'haemolytic' comes from New Latin 'haemolyticus', from Greek 'haima' meaning 'blood' and 'lysis' meaning 'loosening' or 'dissolution'.

'haemolytic' entered English via New/Medical Latin 'haemolyticus' (formed from Greek roots 'haima' + 'lysis'); the spelling 'haem-' (British) later yielded the American simplified form 'hem-' (so 'beta-hemolytic' is the US spelling variant), and the compound 'beta-haemolytic' became established in medical microbiology to describe the β-type of haemolysis.

Initially the elements referred more generally to 'blood dissolution' from the Greek roots, but over time the combined term 'beta-haemolytic' came to be a specific technical descriptor meaning 'producing complete red blood cell lysis (β-type) on blood agar' in microbiology.