'banquet' originates from Old French, specifically the word 'banquet', a diminutive formed from 'banc'/'banque', where 'banc' meant 'bench'.

'banquet' changed from Old French 'banquet' (a little bench) and entered Middle English as 'banquet'; the sense shifted from a bench/board (on which food might be served) to a meal or feast, yielding the modern English 'banquet'.

Initially it referred to a 'small bench' or an occasion involving a bench/board; over time it evolved into the meaning 'a large formal meal or feast', which is the modern sense.