In the organisation of the Catholic Church and of the Anglican Communion^[1] an ordinariate is a pre- or pseudo-diocesan ecclesiastical structure, of geographical or personal nature, headed by an ordinary who is not necessarily a bishop.

An ordinariate can be:

• an ordinariate for the faithful of Eastern rites in one or more countries (for Catholics of Armenian or Byzantine rite, usually)
• a military ordinariate, for the troops of a nation
• a personal ordinariate, also known as an Anglican ordinariate^[2][3] (a Catholic jurisdiction for those of the Anglican patrimony)
• a missionary jurisdiction, the Eastern Catholic equivalent of an apostolic prefecture, e.g. the former Ordinariate of Asmara
• the diocesan curia (in German use [Ordinariat], cf. English chancery)
• an ordinariate for an academic community, notably the former (unique?) Ordinariate for foreign students in Belgium