What is the difference between Great Britain england UK and British commonwealth?

Great Britain refers to the island consisting of England, Scotland and Wales.

England is a country constituent of the United Kingdom, which is the official name of the country that also includes Scotland, Wales and Northern Ireland.

The United Kingdom (UK) is a sovereign country located off the northwestern coast of mainland Europe. The UK is a constitutional monarchy with a parliamentary democracy and a member state of the European Union.

British Commonwealth is an international organisation whose members are independent and equal sovereign states. The Commonwealth of Nations was established in 1926 and is composed of 53 member states. The majority of these states are former colonies of the British Empire.