From Wikipedia, the free encyclopedia.
For centuries, there have been autonomous Eastern-Rite Catholic or churches, i.e., hierarchical churches in full communion with the Vatican, but which the Pope allows to follow customs and rules like those of the Eastern Orthodox Church, (e.g., they confirm newly baptized infants via chrismation, they have married priests, their churches have iconostases, etc.). Similarly, there are also Western Orthodox churches (or Western-Rite Orthodox churches) that are in full communion with the Eastern Orthodox Church, but whose practices resemble those of Anglicans (e.g., Episcopalians). However, they are neither an autocephalous nor fully autonomous, but report ultimately to the Patriarch of Antioch.
Or, expressed in a different way:
The Western Orthodox Church is not part of the Western or Roman Catholic Church but is a part of the Eastern Orthodox Church. Therefore the Western Orthodox Church is not in communion with Catholic Church.
Similarly the Eastern Catholic Church is not part of of the Eastern Orthodox Church but is part of the Catholic Church. Therefore the Eastern Catholic Church is not in communion with the Eastern Orthodox Church.