An Etymological Dictionary of the German Language/Back
Back, n., ‘a deep wooden dish, in which food is served for a certain number of the crew’; borrowed, like many technical terms of sea-life, from LG.; LG. back, ‘dish,’ E. back (‘tub, vat’); comp. ModFr. bac, ‘brewer’s vat or tub,’ borrowed from this word or the Du. bak. It has been derived from Late Lat. bacca, ‘water vessel,’ whence also Fr. bac, ‘ferryboat,’ Du. bak, E. bac, ‘a flat-bottomed boat.’ Probably Becken is allied to it.