In the organisation of the Catholic Church and of the Anglican Communion an ordinariate is a pre- or pseudo-diocesean ecclesiastical structure, of geographical and/or personal nature, headed by an ordinary who is not necessarily a bishop.
An ordinariate can be:
an ordinariate for the faithful of eastern rite(s) in one or more countries
a military ordinariate, for the troops of a nation
a personal ordinariate, also known as an Anglican ordinariate
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
