ransom: [13] Heavily disguised, ransom is the same word ultimately as redemption. It was borrowed from Old French ransoun, which, much weathered over the centuries, was descended from Latin redemptiō, source of English redemption. The etymological notion underlying the word is thus of money paid to ‘redeem’ or rescue a hostage. => redemption
ransom (n.)
c. 1200, "sum paid for the release of a prisoner or captured man," from Old French ranson (Modern French rançon), earlier raenson "ransom, redemption," from Latin redemptionem (nominative redemptio) "a redeeming," from redimere (see redeem).
ransom
early 14c., from ransom (n.). Related: Ransomed; ransoming.