Northern Ireland different from Republic of Ireland
Unionist
Ulster, strictly speaking, refers to the province of Ulster, of which six of nine historical counties are in Northern Ireland. The term "Ulster" is widely used by unionists and the British press as shorthand for Northern Ireland, and is also favoured by Ulster nationalists. In the past, calls have been made for Northern Ireland's name to be changed to Ulster. This proposal was formally considered by the Government of Northern Ireland in 1937 and by the UK Government in 1949 but no change was made.
The Province refers to the historic Irish province of Ulster but today is used by some as shorthand for Northern Ireland. The BBC, in its editorial guidance for Reporting the United Kingdom, states that "the Province" is an appropriate secondary synonym for Northern Ireland, while "Ulster" is not. It also suggests that "people of Northern Ireland" is preferred to "British" or "Irish", and the term "mainland" should be avoided in reporting about Great Britain and Northern Ireland.Nationalist
North of Ireland – used to avoid using the name given by the British-enacted Government of Ireland Act 1920.
The Six Counties (na Sé Chontae) – the Republic of Ireland is similarly described as the Twenty-Six Counties. Some of the users of these terms contend that using the official name of the region would imply acceptance of the legitimacy of the Government of Ireland Act.
The Occupied Six Counties – used by some republicans. The Republic, whose legitimacy is similarly not recognised by republicans opposed to the Belfast Agreement, is described as the "Free State", referring to the Irish Free State, which gained independence (as a Dominion) in 1922.
British-Occupied Ireland – Similar in tone to the Occupied Six Counties, this term is used by more dogmatic republicans, such as Republican Sinn Féin, who still hold that the Second Dáil was the last legitimate government of Ireland and that all governments since have been foreign-imposed usurpations of Irish national self-determination.
not same as not identical to distinct from separate from unlike