An Etymological Dictionary of the German Language/Annotated/Backe
Backe (1.), Backen, masculine, especially used in the compounds with Asch-, Hinter-, hence the literal meaning, ‘buttock.’ The correct High German form, which has the regular permutation of k to ch, is seen in Middle High German bache, Old High German bahho, ‘ham, flitch of bacon’ (yet Middle High German also ars-backe, masculine), which as ‘bacon’ made its way into Old French, and thence into English also. Although it has been connected by the linguistic instinct of Modern High German with the following word, they are not allied; it is more probable that Backe and the stem bak, discussed under Backbord, is most closely connected with it.
Backe (2.), masculine, feminine, also Backen, masculine (the latter especially in the compounds Backenzahn, -streich), ‘cheek’; from Middle High German backe, masculine, ‘jaw, jawbone, cheek.’ Old High German has the doublets baccho (whence the Middle High German and Modern High German ck) and bahho, which produce Middle High German bache. Compare Middle High German kinnebache beside kinnebacke, which compound too, even in Old High German (as chinni-bahho), is more frequent than the simple word; compare Old Saxon kinni-bako, Dutch kinnebakken. It is still uncertain whether Latin bucca, ‘cheek,’ is allied to it; its initial b might have arisen from bh, as in barba (see Bart); but the two differ in meaning; while the Latin signifies ‘the inflated cheek,’ the German word originally denoted ‘jaw.’