A Christian denomination is a distinct religious body within Christianity, identified by traits such as a name, organisation, leadership and doctrine. Individual bodies, however, may use alternative terms to describe themselves, such as church or sometimes fellowship. Divisions between one group and another are defined by authority and doctrine; issues such as the nature of Jesus, the authority of apostolic succession, eschatology, and papal primacy may separate one denomination from another. Groups of denominations — often sharing broadly similar beliefs, practices, and historical ties — are sometimes known as "branches of Christianity" or "denominational families".
Individual Christian groups vary widely in the degree to which they recognize one another. Several groups claim to be the direct and sole authentic successor of the church founded by Jesus Christ in the 1st century AD. Others, however, believe in denominationalism, where some or all Christian groups are legitimate churches of the same religion regardless of their distinguishing labels, beliefs, and practices. Because of this concept, some Christian bodies reject the term "denomination" to describe themselves, to avoid implying equivalency with other churches or denominations.
The Catholic Church, the largest Christian denomination with roughly 1.2 billion members—slightly over half of all Christians worldwide—is the world's second largest religious denomination after Sunni Islam. However, the Catholic Church does not view itself as a denomination, but as the original pre-denominational church. This view is rejected by other Christian denominations. Protestant denominations account for approximately 37 percent of Christians worldwide. Together, Catholicism and Protestantism (including Anglicanism, and other denominations sharing historical ties) comprise Western Christianity. Western Christian denominations prevail in Western, Northern, Central and Southern Europe, Sub-Saharan Africa, the Americas and Oceania.