The English noun commonwealth dates from the fifteenth century. The original phrase "common-wealth" or "the common weal" comes from the old meaning of "wealth," which is "well-being". The term literally meant "common well-being". Thus commonwealth originally meant a state or nation-state governed for the common good as opposed to an authoritarian state governed for the benefit of a given class of owners. The word relates to the Latin phrase res publica meaning "public affairs" or "the state", from which the English word republic arises.

Today the term is more general and means a political community.

The type of community indicated by the term commonwealth varies. For instance, in different contexts it might indicate:

• a political unit founded in law by agreement of the people for the common good;
• a federated union of constituent states;
• a community of sovereign states;
• a republic;
• a democratic constitutional monarchy;

When capitalized, "Commonwealth" normally refers to the 53 member Commonwealth of Nations.

Commonwealth of Nations

The Commonwealth of Nations — formerly the "British Commonwealth" — is a loose confederation of nations which were formerly members of the British Empire (with one exception, Mozambique, which was a Portuguese possession). The Commonwealth's membership includes both republics and monarchies. The (appointed, not hereditary) head of the Commonwealth of Nations is Queen Elizabeth II. She also reigns as monarch directly in a number of states, known as Commonwealth Realms, notably the United Kingdom, Australia, Canada, Jamaica and New Zealand. The Commonwealth of Nations is sometimes referred to as the New Commonwealth in a British context.

Commonwealth of Independent States

The Commonwealth of Independent States (CIS) is a loose alliance or confederation consisting of 10 of the 15 former Soviet Republics, the exceptions being Turkmenistan, Lithuania, Latvia, Estonia and Georgia. Georgia left the CIS in August 2008 after a clash with Russia over South Osetia. Its creation signaled the dissolution of the Soviet Union, its purpose being to "allow a civilized divorce" between the Soviet Republics. The CIS has developed as a forum by which the member-states can co-operate in economics, defense and foreign policy.

Australia

The term also served when six Australian colonies federated to form the Commonwealth of Australia in 1901. The Commonwealth of Australia Constitution Act created a federal system, in which power is divided between the federal, or national, government and the States — the evolved status of the colonies. The Constitution stipulated that Australia was a constitutional monarchy, where the Head of State is the British (or, since 1942, Australian) monarch, who is represented at the federal level by a Governor-General, and at the state level by six Governors, one for each state. The Parliament of Australia was derived from the British, Canadian and American systems to form a uniquely Australian system. It is largely based on the British Westminster System, adopting many of its practices and precedents, but with a similar structure — House of Representatives, and Senate — to the U.S. Congress. In an Australian context, the term "Commonwealth" (capitalised) thus refers to the federal government and "Commonwealth of Australia" is the official name of the country.