Catholicity (from Ancient Greek: καθολικός, romanized: katholikós, lit. 'general', 'universal', via Latin: catholicus) is a concept pertaining to beliefs and practices that are widely accepted by numerous Christian denominations, most notably by those Christian denominations that describe themselves as catholic in accordance with the Four Marks of the Church, as expressed in the Nicene Creed formulated at the First Council of Constantinople in 381: "[I believe] in one, holy, catholic, and apostolic Church." The English adjective catholic is derived from the Ancient Greek adjective καθολικός (romanized: katholikos), meaning "general", "universal". Thus, "catholic" means that in the Church the wholeness of the Christian faith, full and complete, all-embracing, and with nothing lacking, is proclaimed to all people without excluding any part of the faith or any class or group of people. An early definition for what is "catholic" was summarized in what is known as the Vincentian Canon in the 5th century Commonitory: "what has been believed everywhere, always, and by all."
This is distinct from the capitalized word Catholic, referring specifically to the Catholic Church and often, further, the Roman Catholic Church, used especially in ecumenical contexts and in countries where other churches use the term catholic, to distinguish it from broader meanings of the term. Though the community led by the pope in Rome is known as the Catholic Church, the traits of catholicity, and thus the term catholic, are also ascribed to denominations such as the Eastern Orthodox Church, the Oriental Orthodox Church, and the Assyrian Church of the East. It also occurs in the language of churches that decisively split from the Roman Catholic Church, like Lutheranism and Anglicanism, as well as Independent Catholicism, Old Catholicism and other Christian denominations. While traits used to define catholicity, as well as recognition of these traits in other denominations, vary among these groups, such attributes include formal sacraments, an episcopal polity, apostolic succession, highly structured liturgical worship, and other shared Ecclesiology.
