An Etymological Dictionary of the German Language/Annotated/Mulm

Mulm, masculine, ‘loose, dry mould, dust,’ first recorded in Modern High German, but probably of an earlier origin; allied to the root mal, ‘to grind,’ literally ‘to pulverise,’ with which Gothic mulda, ‘dust, earth,’ and English mould are connected; see under Maulwurf. Compare also Grand.