'lysin' originates from New Latin/modern scientific formation, specifically from the Greek word 'lysis', where the root 'lys-' meant 'loosening, dissolution' and the suffix '-in' indicated a substance or protein.

'lysin' changed from Greek 'lysis' through New Latin 'lysis' and later modern scientific coinage to become the noun 'lysin' referring to a substance that causes lysis.

Initially, it meant 'a loosening or dissolution' (the process of lysis), but over time it evolved into its current meaning of 'a substance or enzyme that causes lysis (breakdown) of cells or biological structures.'