'beau' originates from French, specifically the word 'beau', where 'beau' meant 'handsome' or 'fine'.

'beau' changed from Old French forms such as 'bel'/'beal', ultimately from Latin 'bellus', and was borrowed into English (from French) as 'beau' in the modern form.

Initially it meant 'beautiful' or 'handsome' (in French), but in English it evolved to refer both to a 'handsome or fashionable man' and to a 'male admirer' or 'boyfriend'.