The United Kingdom (UK) is often incorrectly referred to as England, Britain, or Great Britain. In fact, the UK is the union of four constituent countries: England, Scotland, Wales, and Northern Ireland. The name United Kingdom is short for: The United Kingdom of Great Britain and Northern Ireland. Great Britain refers to one of the two major islands that comprise the British Isles; it is made up of England, Scotland, and Wales.
Some people likely confuse England as being the same as the whole of Great Britain or the United Kingdom because of England's dominance and power in Great Britain and the UK. As the largest part of the UK, England holds about 84% of the population of the entire United Kingdom and geographically covers approximately 57% of Great Britain. Moreover, London, as England's capital and the largest city in the UK, has been the ruling center of government for the United Kingdom since 1707. In 1999, however, Scotland and Wales were granted some self governing powers, and the Scottish Parliament and the National Assembly of Wales now has some ruling power.
It is also easy to confuse the term "British" as meaning the same as "English." "British" correctly refers to any people from Great Britain and not only the "English" from England. For the most part, people from England, Scotland, and Wales, prefer to be referred to as "English," "Scottish," and "Welsh" respectively, as opposed to the more generic "British" term.
Scotland occupies the top portion of Great Britain. It was a separate country from England until 1603, when King James VI, the king of Scotland, inherited the English throne as well. The countries, however, remained separate until the Acts of Union were passed in 1707 merging the English and Scotish parliaments into a single United Kingdom parliament. By this time, England already controlled Wales and Ireland.
Wales, on the other hand, occupies a sort of southwestern region of Great Britain and is separated from Ireland and Northern Ireland by the Irish Sea. While its complex history with England has spanned many centuries, it has been officially considered separate from England since 1955.
The final component of the United Kingdom is Northern Ireland, which was established in 1920 and is independent from the Republic of Ireland. It is the only of the four UK countries that is located on a different island. Both Ireland and Northern Ireland occupy the island west of Great Britain. These two islands, the Irelands on one hand and Great Britain (England, Scotland, and Wales) on the other, as well as thousands of little islands comprise the British Isles. The Channel Islands, The Isle of Wight, the Hebrides, and the Isle of Man are some of the more well-known small islands in the British Isles.