An Etymological Dictionary of the German Language/Annotated/Lebkuchen
Lebkuchen, masculine, ‘gingerbread,’ from the equivalent Middle High German lëbekuocke, masculine, allied to the equivalent Middle High German lëbezelte. The derivation of lëb-, from Slavonic lipa, ‘lime-time,’ Polish lipiec, ‘finest honey (lime-tree honey),’ is improbable; Latin lîbum, too, hardly suffices to explain the High German word. Middle High German lëbe- is more probably a graded form of Middle High German leip (see Laib), ‘bread.’ Or is it connected with ModSlov. lepenj, ‘a sort of cake’?