A Bicameral system of government is one where there are two legislative or parliamentary chambers. The word comes from the Latin "bi" (meaning two) and "camera" (meaning chamber). In most cases they have different numbers of members. The smaller legislature is often called the "upper house" or "senate" and the larger is called the "lower house", and sometimes also called by another name such as "assembly" or "commons". For legislation to be passed, bicameral legislatures normally need a majority of members of both chambers to vote for the legislation.