Debates in the main chambers of the European Parliament, the National Assembly for Wales, the Northern Ireland Assembly and the Scottish Parliament which all members can attend are called plenary sessions.
The term plenary, derived from the Latin for full, is used to distinguish these sessions from committee hearings, when only the committee members may participate.
In the European Parliament, plenaries are held once a month in Strasbourg from a Monday evening to Thursday afternoon. Additional mini plenary sessions take place roughly six times a year in Brussels and usually last for two days.
The Welsh Assembly holds plenary sessions on Tuesday and Wednesday afternoons.
The Northern Ireland Assembly's plenary sessions take place on Mondays and Tuesdays.
Plenaries in the Scottish Parliament are held on Wednesday afternoons and all day on Thursdays.
The term is not commonly used in relation to debates in Westminster.