An Etymological Dictionary of the German Language/Annotated/Lei
Lei, Leie, masculine and feminine, ‘rock, stone’ (in proper names like Lorelei), from Middle High German lei, leie, feminine, ‘rock, stone,’ also ‘paved way, schist,’ corresponding to Old Saxon leia, feminine ‘rock.’ Further cognates, whether in the Teutonic or non-Teutonic languages, are uncertain (allied perhaps to Greek λᾶας, ‘stone’?). It has been assumed that Italian lavagna, ‘slate,’ was borrowed from the German cognates.