An Etymological Dictionary of the German Language/Annotated/Buckel

Buckel (1.), masculine, ‘boss, stud,’ from Middle High German buckel, masculine, feminine, ‘boss of a shield’; from Old French bocle (whence French boucle, ‘buckle’), which is based on Latin buccula, ‘beaver of a helmet, boss.’

Buckel (2.), Puckel, masculine, ‘back, hump,’ from Middle High German buckel. The Swiss bukel (not *buχel) points to a primary form bugg- (see biegen, Bühel, Bügel), not directly to bücken, from biegen (root bug). Buckel is literally ‘a curve, bend.’