A Commonwealth realm is any one of the 16 sovereign states that recognize Elizabeth II of the United Kingdom as their Queen and head of state. In these states she is officially known as the Monarch of that state, not as the monarch of Great Britain. For example, in Canada she is known as "Her Majesty Queen Elizabeth II, Queen of Canada" or simply, the Queen of Canada.
The United Kingdom, also considered a Commonwealth realm.
The Commonwealth realms is a part, but should be distinguished from, the Commonwealth of Nations which is an organization of mostly former British colonies[?], most of which do not recognize the British monarch as head of state.