'baillie' originates from Old French 'baillie' (variant of 'bailli'), ultimately from Late Latin roots related to 'baiulus'/'bajulus', where the root meant 'to bear, to carry' (responsibility).

'baillie' changed from Old French 'baillie'/'bailli' into Middle English forms such as 'bailie' or 'baillie', and it became the established Scots municipal title 'baillie'.

Initially it meant 'one who bears responsibility' or 'steward/bailiff', but over time it became specialized to mean 'a municipal magistrate or civic officer in Scotland'.