An Etymological Dictionary of the German Language/Annotated/Beule

Beule, feminine, ‘boil, swelling,’ from the equivalent Middle High German biule, Old High German bûlla, *bûllea, feminine, ‘blister’; compare Anglo-Saxon bŷle, English bile (also boil), Dutch buil, ‘boil’; Gothic *bûljô, ‘swelling,’ is connected with Gothic ufbauljan, ‘to inflate,’ and stands probably for *bûgwliô, properly Buckel (hump); akin to biegen.