REAM (either through Du. riem, or O.Fr. rayme, reyme, mod. rame, Med. Lat. risma, from Arabic rizmah, bale or bundle), a certain quantity of paper, viz. 20 quires containing 24 sheets each or 480 sheets; a " printer's ream " contains 215 quires or 516 sheets. The word owes its introduction into Europe to the Moors, who were the originators of the paper manufactured in Spain. Its original meaning was simply bundle, applied either to paper or clothes.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)