A metochion is an ecclesiastical embassy church, usually from one autocephalous or autonomous church to another. The term is also used to refer to a parish representation (or dependency) of a monastery.
In the former case, the local territorial church grants a plot of land or a church building for the use of the foreign church being represented, and the location is then considered to belong canonically to the foreign church. Services held there are often in the language appropriate to the church being represented, and the congregation is often made up of immigrants or visitors from the nation associated with that church. Typically, a metochion presence on the territory of an autocephalous church is limited to only a few parishes at most.
In the case of a monastic metochion, such a parish church is a dependency on a particular monastic community, perhaps receiving clergy from that community or other forms of support.