The phrase "a gaol" is correct and usable in written English.
It is typically used in British English to refer to a prison or jail.
Example: "After the trial, the judge sentenced him to five years in a gaol for his crimes."
Alternatives: "a prison" or "a jail".
The theatre has been likened to a gaol, a workhouse, a power station and a jam factory.
He concluded thus: "It is the view of the Commission that every prison officer who served at Grafton during the time it was used as a gaol for intractables must have known of its brutal regime.
A gaol from the same time reflects Tasmania's convict past.
In addition to courts, and now a gaol, Chester Castle also housed a garrison of soldiers.
God's House tower continued to be used as a gaol, but was criticised by inspectors.
In 1855 its role as a gaol was concluded, and the building fell into disuse.
A building referred to as "Somerset castle" is believed to have been built around 1280 as a county gaol, with a visitor in 1579 describing the remaining portion as "an old tower embattled about castle-like".
During a border skirmish he killed James Burne, a Scot, for which he was imprisoned at a London gaol, but his release was secured by the intervention of Robert Devereux, 2nd Earl of Essex.
There is nothing here of the atmosphere of a Victorian gaol.
Saif was instrumental in persuading his father to compensate the victims of Lockerbie and later, when al-Megrahi was released from a Scottish gaol, it was Saif who brought him back to Tripoli.
But when he found a volume by Dante in another cell, he wrote: "Strange and beautiful it seemed to me that the sorrow of a single Florentine in exile should, hundreds of years afterwards, lighten the sorrow of some common prisoner in a modern gaol".
