Source : Webster's Revised Unabridged Dictionary (1913)

Senate \Sen"ate\, n. [OE. senat, F. s['e]nat, fr. L. senatus,
   fr. senex, gen. senis, old, an old man. See {Senior}, {Sir}.]
   1. An assembly or council having the highest deliberative and
      legislative functions. Specifically:
      (a) (Anc. Rom.) A body of elders appointed or elected from
          among the nobles of the nation, and having supreme
          legislative authority.

                The senate was thus the medium through which all
                affairs of the whole government had to pass.
                                                  --Dr. W.
                                                  Smith.
      (b) The upper and less numerous branch of a legislature in
          various countries, as in France, in the United States,
          in most of the separate States of the United States,
          and in some Swiss cantons.
      (c) In general, a legislative body; a state council; the
          legislative department of government.

   2. The governing body of the Universities of Cambridge and
      London. [Eng.]

   3. In some American colleges, a council of elected students,
      presided over by the president of the college, to which
      are referred cases of discipline and matters of general
      concern affecting the students. [U. S.]

   {Senate chamber}, a room where a senate meets when it
      transacts business.

   {Senate house}, a house where a senate meets when it
      transacts business.

Source : WordNet®

senate
     n 1: assembly possessing high legislative powers
     2: the upper house of the United States Congress [syn: {United
        States Senate}, {US Senate}]