Britain

Britain, Great Britain, the British Isles, England, etc.

1. Use of these terms causes confusion. Great Britain refers to the largest island in the group, which is divided between England, Scotland, and Wales. Politically, it means these three countries (since the Act of Union of 1707), and excludes Northern Ireland, the Isle of Man, and the Channel Islands. Britain is an informal term with no official status; it often means the same as Great Britain but can also include Northern Ireland.

2. The British Isles is a geographical term for the group of islands including Great Britain and Ireland and also the smaller islands around them, such as the Isle of Man and the Scottish islands. The United Kingdom is a political term, in full the United Kingdom of Great Britain and Northern Ireland, and includes these countries but not usually the Isle of Man or the Channel Islands.

3. England strictly refers to a single political division of Great Britain, but it is commonly substituted for (Great) Britain, especially in AmE. This causes some offence in Scotland and Wales, and should be avoided in BrE. The same is true of the corresponding ethnic designation English used instead of British.

4. There is, surprisingly, no convenient general term for a citizen of the United Kingdom: Briton is normally confined to historical (or jocular) reference, and Britisher is AmE.