<P> The modern word Senate is derived from the (Latin) word senātus (senate), which comes from senex, "old man". The members or legislators of a senate are called senators . The Latin word senator was adopted into English with no change in spelling . Its meaning is derived from a very ancient form of social organization, in which advisory or decision - making powers are reserved for the eldest men . For the same reason, the word senate is correctly used when referring to any powerful authority characteristically composed by the eldest members of a community, as a deliberative body of a faculty in an institution of higher learning is often called a senate . This form adaptation was used to show the power of those in body and for the decision - making process to be thorough, which could take a long period of time . The original senate was the Roman Senate, which lasted until 580 (various efforts to revive it were made in Medieval Rome). In the Eastern Roman Empire, the Byzantine Senate continued until the Fourth Crusade, circa 1202--1204 . </P> <P> Modern democratic states with bicameral parliamentary systems are sometimes equipped with a senate, often distinguished from an ordinary parallel lower house, known variously as the "House of Representatives", "House of Commons", "Chamber of Deputies", "National Assembly", "Legislative Assembly", or "House of Assembly", by electoral rules . This may include minimum age required for voters and candidates, proportional or majoritarian or plurality system, and an electoral basis or collegium . Typically, the senate is referred to as the upper house and has a smaller membership than the lower house . In some federal states senates also exist at the subnational level . In the United States all states with the exception of Nebraska (whose legislature is a unicameral body called the "Legislature" but whose members refer to themselves as "senators") have a state senate . There is also the US Senate at the federal level . Similarly in Argentina, in addition to the Senate at federal level, eight of the country's provinces, Buenos Aires, Catamarca, Corrientes, Entre Ríos, Mendoza, Salta, San Luis (since 1987) and Santa Fe, have bicameral legislatures with a Senate . Córdoba and Tucumán changed to unicameral systems in 2001 and 2003 respectively . </P> <P> In Australia and Canada, only the upper house of the federal parliament is known as the Senate . All Australian states other than Queensland have an upper house known as a Legislative council . Several Canadian provinces also once had a Legislative Council, but these have all been abolished, the last being Quebec's Legislative council in 1968 . </P> <P> In Germany, the last Senate of a State parliament, the Senate of Bavaria, was abolished in 1999 . </P>

Which term refers to the senate leader who