A catholicate or catholicosate is the area of responsibility (territorial or otherwise) of a catholicos, a leader within any of the several churches of Eastern Christianity, especially those regarded as Oriental Orthodoxy. The word is derived from the Greek Καθολικος, meaning "wholeness."
While a catholicos is sometimes considered to correspond to a bishop in the Roman Catholic and Protestant traditions, a catholicate is typically a larger and more significant organizational division than a bishopric, archdiocese or episcopal see. Catholicates often have distinct cultural traditions established over many centuries.
For example, within the Armenian Apostolic Church there are two catholicosates: the Catholicosate of Etchmiadzin, Etchmiadzin-Armenia, and the Catholicosate of the Great House of Cilicia, Antelias-Lebanon. In the 10th century, when Armenia was devastated by Seljuks, the Armenian church took refuge in Cilicia. In the 15th century, when Armenia was relatively peaceful compared to Cilicia, a new catholicos was elected in Etchmiadzin.
While some traditions favor the English language spelling "catholicate" and others favor "catholicosate." There is a degree of inconsistency in this regard. Others spellings, including "catholicossate", are seen as well.