early 14c., "to heat, rub with the hands to make warm," from O.Fr. chaufer
, from V.L. *calefare
, from L. calefacere
"to make hot, make warm," from calere
"be warm" (see calorie
) + facere
"to make, do" (see factitious
). Sense of "make sore by rubbing" first recorded 1520s.