From The Art and Popular Culture Encyclopedia
A senate is a deliberative assembly, often the upper house or chamber of a 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. Two of the first official senates were the Spartan Gerousia (Γερουσία) and the Roman Senate.
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.