Politics of the United Kingdom
The UK Parliament is the supreme legislative body in the United Kingdom (i.e., there is parliamentary sovereignty), and Government is drawn from and answerable to it. Parliament is bicameral, consisting of the House of Commons and the House of Lords. There is also a devolved Scottish Parliament and devolved Assemblies in Wales and Northern Ireland, with varying degrees of legislative authority.
Tricameralism
Tricameralism is the practice of having three legislative or parliamentary chambers. It is contrasted with unicameralism and bicameralism, both of which are far more common.