'treatment-associated' originates from the combination of 'treatment' and 'associated', where 'treatment' comes from the Old French 'traitement', meaning 'management' or 'handling', and 'associated' comes from the Latin 'associatus', meaning 'joined' or 'connected'.

'treatment' evolved from the Old French 'traitement' and 'associated' from the Latin 'associatus', eventually forming the modern English term 'treatment-associated'.

Initially, 'treatment' meant 'management' or 'handling', and 'associated' meant 'joined' or 'connected'. Over time, 'treatment-associated' evolved to specifically refer to effects or conditions related to medical treatments.