Gaol - jail
Jail and gaol, meaning 'prison', are the same word, now pronounced in the same way ('jale', IPA: //dʒeɪl). Jail is the spelling to use in everyday English, and is not used in American English; gaol is an archaic usage which survives in official and legal usage. Writers might also care to use it in some historical contexcts - where it is certainly to be read. Until the seventeenth century, according to Hoad, 1996, gaol was pronounced with a hard -g-, 'gay-all' IPA: /geɪ ɔl/, after which the current pronunciation became the accepted. (It is as old.) The two words are derivations of the same original in two different varieties of French, which both contributed them to English.
- The original is a Late Latin gabiola, for a postulated caveola, diminutive of cavea, 'hollow, cavity, den, cage, coop'. There was a not uncommon change of -ea to a more consonatal sound as '-ya' or '-ja' as the Romance languages developed out of Latin: this happened differently in Northern and Parisian forms of French.
- Gaol is the form that developed in Norman French (as gaiole, gayolle or gaole), and was thus the form used in law. (Law French, a fossil of the Norman Conquest was an official loanguage of the courts until finally abandoned in 1731.) So this is the form to be seen in older official use, in Britain. (Middle English forms include gayole, gayhole, gayol, gayll, gaylle, gaill, gaille and gayle.
- Jail is the form adopted in Parisian, or central, French, where it took such forms as jaiole, jaole, jeole, geole and geôle (with soft -g-s) .
Don't confuse gaol with goal - a common typographical error, not detected by most spell-checkers.