An Etymological Dictionary of the German Language/bauchen
bauchen, vb., ‘to steep in hot lye’ (LG. büken, MidLG. bûken), from the equiv. MidHG. bûchen, OHG. *bûhhên; E. to buck (dial. to bouk), for which even a MidE. term bouken occurs a few times, points to AS. *bûcian; to these Swed. byka, Ic. bauka, and Norw. boykja, are allied. The word is, moreover, diffused through most of the Teut. languages, and correctly represents MidHG. bûchen; only in the Bav. dialect is the word unrecorded. Hence the existence of a Teut. verbal root bûk (to which AS. bûc, ‘pail,’ is allied?) is undoubted, and the Rom. cognate, Fr. buer (Ital. bucare), ‘to wash,’ is more probably borrowed from the Teut. than vice versâ. The Kelt. origin of bauchen (Bret. boukat, ‘to soften’) is impossible.