An Etymological Dictionary of the German Language/Annotated/Wachs
Wachs, neuter, ‘wax,’ from the equivalent Middle High German and Old High German wahs, neuter, common to Teutonic in the same sense; compare Old Icelandic vax, Anglo-Saxon weahs, English wax, Low German and Dutch was. Old Slovenian (Russian) voskŭ, Lithuanian wászkas, ‘wax,’ perhaps borrowed from Old Teutonic, are closely related to this word.