Pairs with
下议院 (xiàyìyuàn, lower house / House of Commons). Used to translate every bicameral upper chamber: UK House of Lords, US Senate (also
参议院 cānyìyuàn), Japanese
参议院, French Sénat.
参议院 is more common for the U.S. specifically;
上议院 is the generic/UK-flavored term.