yakstorm said:
British Isles would be the only 'shorten' term you could use to describe both The United Kingdom of Great Britain (official name) and the Republic of Ireland.
You're right, up to a point. The official name is United Kingdom of Great Britain and Northern Ireland. Great Britain is the whole of the British Isles that can be said to be either English, Welsh or Scottish. The main island which forms the greater part of England, Scotland and Wales is called Albion.
The whole thing, i.e. the whole of Grea Britain plus mainland Ireland and any offshore islands included, are the British Isles. At that point it stops being a political name, British Isles is a purely geographical term. It is seen as political though by many in Ireland, and would be more contentious a name than Great Britain and Ireland. Or at least it would be if more than a handful of people in Ireland knew this was happening.