Catholicism is a broad term for the body of the Catholic faith, its theologies and doctrines, its liturgical, ethical, spiritual, and behavioral characteristics, as well as a religious people as a whole.
For many the term usually refers to Christians and churches, western and eastern, in full communion with the Holy See, known alternatively as the Catholic Church or as the Roman Catholic Church. However, many others use the term to refer to other churches with historical continuity from the first millennium.
In the sense of indicating historical continuity of faith and practice, the term "catholicism" is at times employed to mark a contrast to Protestantism, which tends to look solely to the Bible as interpreted on the principles of the 16th-century Protestant Reformation as its ultimate standard. It was thus used by the Oxford Movement.
According to Richard McBrien, Catholicism is distinguished from other forms of Christianity in its particular understanding and commitment to tradition, the sacraments, the mediation between God, communion, and the See of Rome. According to Orthodox leaders like Bishop Kallistos Ware, the Orthodox Church has these things as well, though the primacy of the See of Rome is only honorific, showing non-jurisdictional respect for the Bishop of Rome as the "first among equals" and "Patriarch of the West". Catholicism, according to McBrien's paradigm, includes a monastic life, religious institutes, a religious appreciation of the arts, a communal understanding of sin and redemption, and missionary activity.