Toilet in Ireland. Usually the gent's toilet. Usually covered in piss maybe with a shite in the urinal. Accompanied by humerous and often informative grafitti.
Great stories on the walls in the Jacks! I've piss up to my knees though.
1) Irish slang for toilet. Derived from Union Jack, the British flag.
2) Term referring to Dubliners, since they uphold British traditions more than any others in Ireland. The name comes from when they waved Union Jack flags during a visit from the Queen.