noun
Refers to a national legislative body as a whole. In Japan, 国会 is more common for the Diet, but 議院 is used in formal contexts and compound terms.
議院の役割は法律を制定することです。
The role of parliament is to enact laws.
Refers to one of the houses within a bicameral legislature, such as the House of Representatives or the House of Councillors.
日本の議院は衆議院と参議院の二つから成る。
Japan's parliament consists of two houses: the House of Representatives and the House of Councillors.