A province can mean a principal subdivision of a country, an administrative division within a state, or an administative division within a conquered territory. (For "province" as a jurisdictional subdivision of a Christian church organization or religious order, see province (religion).)
Northern Ireland became known as 'the Province', originally a translation of the Nordic word Ulster - which is one of the four original Irish provinces, and of which Northern Ireland covers two thirds. Northern Ireland is sometimes called a province of the United Kingdom, though not normally by the UK government or the Northern Ireland Assembly.
- Shorter Oxford English Dictionary, 1992