The term Eastern Church is variously used to refer to:

• The Eastern Orthodox Church, or
• Any of the Oriental Orthodox churches, or
• Any of the Eastern Rite Catholic churches, or
• The three groups collectively, when speaking of things they share in common with each other but not with Western churches.

See also Eastern Christianity.

Although there are important theological and dogmatic disagreements among these three groups, nonetheless in some matters of traditional practice that are not matters of dogma, they resemble each other in some ways in which they differ from Catholic and Protestant churches in the West. For example, in all three groups, parish priests administer the sacrament of chrismation to newborn infants just after baptism; that is not done in Western churches. All three groups have weaker rules on clerical celibacy than those of the Latin Rite (i.e. Western) Catholic churches, in that, although they forbid marriage after ordination, they allow married men to become priests (but not bishops). For these reasons, it sometimes makes sense to generalize, saying "In the Eastern Church, it is customary to ..." etc.