'bacteriolysin' originates from New Latin/Greek-derived scientific formation, specifically the combining elements 'bacterio-' (from New Latin 'bacterium', ultimately from Greek 'bakterion') and '-lysin' (from Greek 'lysis' via modern scientific usage), where 'bakterion' meant 'small rod' and 'lysis' meant 'loosening' or 'dissolution'.

'bacteriolysin' changed from the 19th/20th-century bacteriological coinage combining 'bacterio-' + 'lysin' (compare related terms like 'bacteriolysis' and 'lysin') and eventually entered modern English scientific usage as 'bacteriolysin'.

Initially, the elements referred generally to 'rod-shaped microbe' and 'loosening/dissolving'; over time the compound came to mean specifically 'an agent that causes lysis of bacteria' in bacteriology.