An Etymological Dictionary of the German Language/Annotated/Ries
Ries, neuter, ‘ream,’ from the equivalent late Middle High German ris (riȥ, rist), masculine, feminine and neuter; in Dutch riem, English ream. These late Teutonic cognates are borrowed from Romance; compare the equivalent Middle Latin and Italian risma, French rame. It is true that the Middle High German form still requires further explanation. The ultimate source of Middle Latin and Italian risma is Arabic rizma, ‘bale, bundle,’ especially ‘packing-paper.’