difference between the United Kingdom, Great Britain, and England?

What is the difference between the United Kingdom, Great Britain, and England? The United Kingdom is a country that consists of Great Britain and Northern Ireland. In fact, the official name of the country is "United Kingdom of Great Britain and Northern Ireland."   Great Britain is the name of the island northwest of France and east of Ireland that consists of three somewhat autonomous regions: England, Wales and Scotland.  Therefore, England is part of Great Britain, which is part of the United Kingdom. The U.K. includes England, Wales, Scotland, and Northern Ireland. England, Wales, Scotland, and Northern Ireland are not countries but the United Kingdom is.  The remaining portion of the island of Ireland (that which is not the U.K.'s Northern Ireland) is an independent country called the Republic of Ireland (Eire).