Parliament
Parliament may refer to the original legislative assembly of England, Scotland, or Ireland and successively of Great Britain and the United Kingdom. Legislative assemblies in some former British colonies may also be named parliaments. Legislative assemblies in general may also be referred to as parliaments, especially if part of a "parliamentary system".
History
A "presidential system" is typically one where the chief executive is directly elected and combines the role of head of state and head of government. A "parliamentary system" separates the roles, with a prime minister being head of government, while the more ceremonial head of state typically being a non-hereditary president or a hereditary monarch.
Parliamentarianism is the dominant form of government in Europe, the Caribbean, and Oceania. Elsewhere in the world, parliamentary countries are less common, but they are distributed through all continents, most often in former colonies of the British Empire that subscribe to a particular brand of parliamentarianism known as the "Westminster system", sometimes contrasted with a "Consensus system" used in most Western European countries.
Parliamentary government
Legislatures called parliaments typically operate under a parliamentary system of government in which the executive is constitutionally answerable to the parliament. This can be contrasted with a presidential system, on the model of the United States' congressional system, which operate under a stricter separation of powers whereby the executive does not form part of, nor is appointed by, the parliamentary or legislative body. Typically, congresses do not select or dismiss heads of governments, and governments cannot request an early dissolution as may be the case for parliaments. Some states have a semi-presidential system which combines a powerful president with an executive responsible to parliament.
Parliaments may consist of chambers or houses, and are usually either bicameral or unicameral—although more complex models exist, or have existed (see Tricameralism). The lower house is almost always the originator of legislation, and the upper house is usually the body that offers the "second look" and decides whether to veto or approve the bills. A parliament's lower house is usually composed of at least 200 members in countries with populations of over 3 million. A notable exception is Australia, which has only 150 members in the lower house despite having a population of over 20 million. The number of seats may exceed 400 in very large countries, especially in the case of unitary states. The upper house customarily has 20, 50, or 100 seats, almost always significantly fewer than the lower house (the British House of Lords is an exception).
A nation's prime minister ("PM") is almost always the leader of the majority party in the lower house of parliament, but only holds his or her office as long as the "confidence of the house" is maintained. If members of parliament lose faith in the leader for whatever reason, they can often call a vote of no confidence and force the PM to resign.
