1) The US Senate 
An upper house, often called a Senate, is one of two chambers of a bicameral legislature, the other chamber being the lower house. A legislature composed of only one house is described as unicameral. == Possible specific characteristics == An upper house is usually different from the lower house in at least one of the following respects: Powers: S...
the second chamber in a two-chamber Parliament; the Senate is the upper house in the federal Parliament
one of two branches of a legislature generally smaller and less representative than the lower branch, as the Senate of the U.S. Congress.