"lie at rest," mid-15c., from Middle French reposer, from Old French repauser (10c.), from Late Latin repausare "cause to rest," from Latin re-, here probably an intensive prefix (see re-), + Late Latin pausare "to stop" (see pause (v.)). Related: Reposed; reposing.
"put, place," mid-15c., from Latin repos-, stem of reponere "put back, set back, replace, restore; put away, lay out, stretch out," from re- "back, away" (see re-) + ponere "to put, place" (see position (n.)). Or perhaps [Klein] formed in Middle English from Old French poser, on model of disposen "dispose."
"rest," c.1500, from Middle French repos (11c.), back-formation from reposer (see repose (v.1)).