jailyoudaoicibaDictYouDict[jail 词源字典]
jail: [13] Etymologically, a jail is a ‘little cage’. The word comes ultimately from Vulgar Latin *gaviola, which was an alteration of an earlier *caveola, a diminutive form of Latin cavea ‘cage’ (source of English cage). It passed into English in two distinct versions: jail came via Old French jaiole; but the Old Northern French form of the word was gaiole, and this produced English gaol.

Until the 17th century gaol was pronounced with a hard /g/ sound, but then it gradually fell into line phonetically with jail. There has been a tendency for British English to use the spelling gaol, while American prefers jail, but there are now signs that jail is on the increase in Britain.
=> cage[jail etymology, jail origin, 英语词源]
jail (n.)youdaoicibaDictYouDict
late 13c., gayhol, from Old North French gaiole and Old French jaole, both meaning "a cage, prison," from Medieval Latin gabiola, from Late Latin caveola, diminutive of Latin cavea "cage, enclosure, stall, coop" (see cave (n.)). Both forms carried into Middle English; now pronounced "jail" however it is spelled. Persistence of Norman-derived gaol (preferred in Britain) is "chiefly due to statutory and official tradition" [OED].
jail (v.)youdaoicibaDictYouDict
"to put in jail," c. 1600, from jail (n.). Related: Jailed; jailing.