A religious denomination is a subgroup within a religion that operates under a common name, tradition, and identity. The term refers to the various Christian denominations (for example, Eastern Orthodox, Roman Catholic, and the many varieties of Protestantism). It is also used to describe the four major branches of Judaism (Orthodox, Conservative, Reform, and Reconstructionist). Within Islam, it can refer to the branches or sects (such as Sunni, Shia and Ahmadiyya), as well as their various subdivisions such as sub-sects, schools of jurisprudence, schools of theology and religious movements. The world's largest religious denomination is Sunni Islam or Roman Catholicism.