The term jurisdiction refers to a given ecclesiastical entity and its parishes. Traditionally and canonically, all the parishes in a given region are governed by one bishop. Jurisdiction is used particularly in those areas where this traditional order has been upset and multiple ecclesiastical entities claim parishes in overlapping territories. Thus, it is a term of distinction which exists mainly because of an uncanonical situation. In English, it has also come to refer generally to all self-governing churches (even those whose territories do not suffer from canonical disorder), in order to reserve the word "church" for the Orthodox Church as a whole, rather than its component parts.
As the 19th century passed into the 20th emigration of people from traditionally Orthodox areas increased, bringing mixes of Orthodox Christians of different ethnic and nationalistic leanings into traditionally non-Orthodox areas, the so-called diaspora. While attempts were made to form a single new canonical episcopate in these countries, notably in North America, each ethnic group relied on their home church for support.
The 20th century also witnessed several waves of emigration from traditionally Orthodox lands, particularly during the two World Wars and the various regional wars and civil wars that followed in their aftermath (such as the Russian Civil War or the Greco-Turkish War). This accelerated the dispersions of Orthodox people and further complicated the ethnic identity issues with political issues. The result has been that some countries which received large numbers of immigrants (such as the United States) ended up with a proliferation of Orthodox groups that depend organizationally on their historical old world churches. The term jurisdiction has become the norm for referring to these various Orthodox groups within the new territories.