From "engines" 1456:
A word to consider next time you open a new ream
of shiny white paper is the Arabic word rizmah. It
means a bale or a bundle. The Spanish made rizmah
into resma, and the French made reyme of it. It
finally became the English word ream -- a bundle of
twenty quires (or 500 sheets) of paper. That
word-trail matches the trail of paper almost perfectly
as it moved from the east to the west.