An Etymological Dictionary of the German Language/Annotated/Besen

by Friedrich Kluge

Besen, masculine, ‘besom, broom,’ from the equivalent Middle High German bësen, bësem, bësme, Old High German bësamo; it corresponds to Anglo-Saxon besma, English besom, Gothic *bisma, which have the same meaning; a pre-Teutonic word of obscure origin; perhaps Beere and Bast are allied. Since the English dialects point to an Anglo-Saxon bîsma, ‘besom,’ it is possible that the word is connected with Bieswind, and the Teutonic root bī̆s, ‘to move in a restless, excited way.’

Besen Latin ferula, 'ferula,' is perhaps connected with this word; base bhes.