standard commercial measure of paper, rem, mid-14c., from Old French reyme, from Spanish resma, from Arabic rizmah "bundle" (of paper), from rasama "collect into a bundle." The Moors brought manufacture of cotton paper to Spain.
The exact path of transmission of the word to English is unclear, and it might have entered from more than one language. An early variant rym (late 15c.) suggests a Dutch influence: compare Middle Dutch rieme, Dutch riem, which probably were borrowed from Spanish during the Hapsburg control of Holland. For ordinary writing paper, 20 quires of 24 sheets each, or 480 sheets; often 500 or more to allow for waste; the count varies slightly for drawing or printing paper.
"to enlarge a hole," especially "to widen or enlarge by the use of a rotary cutter," 1815, a word of "somewhat doubtful origin" [OED], but it is probably a southwest England dialectal survival from obsolete Middle English reme "to make room, open up, extend by stretching."
This is from Old English ryman "widen, extend, enlarge," from Proto-Germanic *rumijan (source also of Old Saxon rumian, Old Norse ryma, Old Frisian rema, Old High German rumen, German räumen"to make room, widen"), from *rumaz "spacious" (see room (n.)). Related: Reamed; reaming; reamer.
Especially with out (adv.). The slang meaning "to cheat, swindle" is recorded by 1914; the sexual sense is attested by 1942. To ream (someone) out in the sense of "to scold, reprimand" is recorded from 1950; earlier it was used of gun barrels, machinery, etc., "to remove (a jam or defect) by reaming" (1861).
"cream," later also "cream-like froth on any liquid," a word now dialectal or obsolete, Old English ream, from Proto-Germanic *raumoz (source also of Middle Dutch and Dutch room, German Rahm), a word of uncertain origin. Related: Reamy.