Legislature, representative assembly empowered to enact, revise, or repeal the laws or statutes of a community. The earliest modern legislatures were the British Parliament and the French States-General, which were forerunners of the contemporary bicameral system of upper and lower houses. In the United States the 2 chambers are the Senate and the House of Representatives, which together are called the Congress. In most bicameral systems both chambers must approve a bill before it becomes law. Under a parliamentary system, like Britain's or Canada's, the prime minister, who heads the government, remains in power only as long as his or her party retains a majority in the main legislative chamber. Under the U.S. system, the president's stay in office is independent of the majority party in the legislature.