'harbinger' originates from Old French/Anglo-French, specifically the word 'herbergere' (also attested as 'herberger'), where the element 'herberg-' meant 'to provide lodging' and Frankish/Germanic 'hari/harja' meant 'army'.

'harbinger' changed from Old French 'herbergere' (or Anglo-French forms) into Middle English forms such as 'herbenger'/'harbenger' and eventually became the modern English word 'harbinger'.

Initially, it meant 'one who provides lodging (especially for an army or travelling party)', but over time it evolved into the current meaning 'one who precedes or foreshadows; a forerunner or omen'.