Parliamentary system of government

A parliamentary system is a system of democratic governance of a state where the executive branch derives its democratic legitimacy from its ability to command the confidence of the legislative branch, typically a parliament, and is also held accountable to that parliament. In a parliamentary system, the head of state is usually a different person from the head of government. This is in contrast to a presidential system, where the head of state often is also the head of government and, most importantly, the executive branch does not derive its democratic legitimacy from the legislature.

Countries with parliamentary systems may be constitutional monarchies, where a monarch is the head of state while the head of government is almost always a member of parliament (such as the United Kingdom, Denmark, Sweden and Japan), or parliamentary republics, where a mostly ceremonial president is the head of state while the head of government is regularly from the legislature (such as Ireland, Germany, India and Italy). In a few parliamentary republics, such as Botswana, South Africa, and Suriname, among some others, the head of government is also head of state, but is elected by and is answerable to parliament. In bicameral parliaments, the head of government is generally, though not always, a member of the lower house.

...
Wikipedia