Catholicism has two main meanings. It is sometimes used to mean the Roman Catholic Church--the term is so used particularly by members of that church. But the term is also used to describe the practices of a larger, more encompassing group of Christian denominations which view themselves as being in historical and doctrinal continuity with Catholic Christianity as it existed before the Great Schisms that separated the church universal into different communions. It is taken from the word catholic, used in the sense of universal, or all-embracing.
Catholicism is difficult to define precisely and somewhat controversial, because not all Christians understand the words 'catholic' and 'catholicism' in the same way. The creeds that define the beliefs of the Christian faith refer to "one holy catholic (and apostolic) Church." Most churches kept the creeds and have considered themselves a part of a wider catholic, or Christian, church even after the Protestant Reformation.
So churchgoers within the same communion (or even within the same denomination) may see themselves as either catholic or protestant. Furthermore, the rites, services and practices within catholic churches can vary greatly.
The largest and best known of these churches is the Roman Catholic Church, whose head is the Pope, the Bishop of Rome. The Roman Catholic Church claimed about 1.07 billion members in 22 distinct churches in communion with the Pope as of 2003 [1]. Next in size are the Eastern Orthodox Churches and the churches of the Anglican Communion.
Among the beliefs common to Catholic Christians that may not be accepted by other Christians are
In addition, the doctrine of Papal Infallibility has separated Christians in the Roman Catholic Church from some other Catholic Christians.
To further complicate matters, Catholic Christians may agree on some issues and not on others, causing further breaks in communion. So there are elements in some catholic congregations that are not present or acceptable in others. Among these divisive issues are: