'councillor' originates from Middle English, formed from the noun 'council' plus the agent suffix '-or'; 'council' ultimately comes from Old French 'conseil' and Latin 'concilium', where 'concilium' meant 'assembly'.

'councillor' changed from Middle English words such as 'counseillour' or 'councelour', which came via Old French 'conseillour', and eventually became the modern English word 'councillor'.

Initially, it meant 'advisor' or 'member of an assembly', but over time it evolved into its common modern meaning of 'an elected member of a local council'.