A senate is a deliberative assembly, often the upper house or chamber of a bicameral legislature or parliament. There have been many such bodies in history, since senate means the assembly of the eldest and wiser members of the society and ruling class. The first official senate was the Roman senate of Ancient Rome.
Many countries currently have an assembly named a senate, composed of senators who may be elected, appointed, have inherited the title, or gained membership by other methods, depending on the country. Modern senates typically serve to provide a chamber of "sober second thought" to consider legislation passed by a lower house, whose members are usually elected.
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 simple social organization in which 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.
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 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.
In Australia and Canada, only the upper house of the federal parliament is known as the Senate. All 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.
Senate membership can be determined either through elections or appointments. For example, elections are held every three years for half the membership of the Australian Senate, the term of a senator being six years. In contrast, members of the Canadian Senate are appointed by the Governor General upon the recommendation of the Prime Minister of Canada, holding the office until they resign, are removed, or retire at the mandatory age of 75. In larger countries, the senate often serves a balancing effect by giving a larger share of power to regions or groups which would otherwise be overwhelmed under strictly popular apportionment.
Alternative meanings 
The terms Senate and Senator, however, do not necessarily refer to a second chamber of a legislature:
- The Senate of Finland was, until 1919, the executive branch and the supreme court.
- In German politics: In the city state Bundesländer of Berlin (Senate of Berlin), Bremen (Senate of Bremen) and Hamburg (Senate of Hamburg), the Senates (Senat in German) are the executive branch, with Senator (Senator) being the holders of ministerial portfolios. In a number of cities, such as Greifswald, Lübeck, Rostock, Stralsund, or Wismar, the city government is also called a Senate. However, in Bavaria, the Senate was a second legislative chamber until its abolition in 1999.
- In German jurisdiction: The term Senat (senate) in higher courts of appeal refers to the "bench" in its broader metonymy meaning, describing members of the judiciary collectively (usually five judges), often occupied with of a particular subject-matter jurisdiction. However, the judges are not called "senators". The German term Strafsenat in a German court translates to Bench of penal-law jurisdiction and Zivilsenat to Bench of private-law jurisdiction. The Federal Constitutional Court of Germany consists of two senates of eight judges each. In its case the division is mostly of an organizational nature, as a matter of dividing the work load; both senates handle the same kind of constitutional cases. At some points in the past, one senate was considered more conservative and the other more liberal, but that is not the case as of 2011.
- In Scotland, judges of the High Court of Justiciary are called Senators of the College of Justice.
- In some, mostly federal countries with a unicameral legislature, some of the legislators are elected differently from the others and are called Senators. In federal countries, such Senators represent the territories, while the other members represent the people at large (this device is used to allow a federal representation without having to establish a bicameral legislature); this is the case with St. Kitts and Nevis, Comoros and Micronesia. In other, non-federal countries, the use of the term Senator marks some other difference between such members and the rest of the legislators (such as the method of selection); this is the case with the States of Jersey, Dominica's House of Assembly and the Saint Vincent House of Assembly.
- In Wales, the National Assembly for Wales debating chamber is called the Senedd, pronounced 'Seneth'.
- A Senate can also be the ruling body of a university.
- In Greece during the early stages of the Greek War of Independence, various local legislative and executive bodies were established by the Greek rebels. Two of them were styled "senate": the Peloponnesian Senate and the Senate of Western Continental Greece.
National senates in the world 
Defunct senates 
Abolished in favor of
New constitution adopted
* A Greek Senate was reestablished in 1927, and abolished again in 1935.
** A South African Senate was reconvened between 1994 and 1997, before being replaced by the National Council of Provinces.
***The Philippine Senate was abolished and restored twice. A new constitution in 1935 abolished the Senate but an amendment in 1941 resorted it in 1945. In 1972, the legislature was closed, and a passage of a new constitution in 1978 confirmed the abolition of the Senate; an approval of a new constitution in 1987 restored it.
See also