A prime minister, premier or chief of cabinet is the head of the cabinet and the leader of the ministers in the executive branch of government, often in a parliamentary or semi-presidential system. Under those systems, a prime minister is not the head of state, but rather the head of government, serving under either a monarch in a democratic constitutional monarchy or under a president in a republican form of government. In parliamentary systems fashioned after the Westminster system, the prime minister is the presiding and actual head of government and head/owner of the executive power. In such systems, the head of state or their official representative (e.g., monarch, president, governor-general) usually holds a largely ceremonial position, although often with reserve powers. Under some presidential systems, such as South Korea and Peru, the prime minister is the leader or most senior member of the cabinet, not the head of government. In many systems, the prime minister selects and may dismiss other members of the cabinet, and allocates posts to members within the government. In most systems, the prime minister is the presiding member and chairman of the cabinet. In a minority of systems, notably in semi-presidential systems, a prime minister is the official appointed to manage the civil service and execute the directives of the head of state. Today, the prime minister is often, but not always, a member of the legislature or its lower house, and is expected with other ministers to ensure the passage of bills through the legislature. In some monarchies the monarch may also exercise executive powers (known as the royal prerogative) without the approval of parliament. As well as being head of government, being prime minister may require holding other roles or posts—the prime minister of the United Kingdom, for example, is also First Lord of the Treasury and Minister for the Civil Service. In some cases, prime ministers may choose to hold additional ministerial posts (e.g. when the portfolio is critical to that government's mandate): during the Second World War, Winston Churchill was also Minister of Defence (although there was then no Ministry of Defence). Another example is the Thirty-fourth government of Israel , when Benjamin Netanyahu at one point served as the prime minister and minister of Communications, Foreign Affairs, Regional Cooperation, Economy, Defense and Interior. Etymology The term "prime minister" is attested in 17th Century sources referring to Cardinal Richelieu, after he