The word catholic (with lowercase c; derived via Late Latin catholicus, from the Greek adjective (katholikos), meaning “universal”) comes from the Greek phrase (katholou), meaning “on the whole”, “according to the whole” or “in general”, and is a combination of the Greek words meaning “about” and meaning “whole”.
The word in English can mean either “including a wide variety of things; all-embracing” or “of the Roman Catholic faith” as “relating to the historic doctrine and practice of the Western Church.”. (“Catholicos, the title used for the head of some churches in Eastern Christian traditions, is derived from the same linguistic origin.)
The term Catholic (usually written with uppercase C in English) was first used to describe the Christian Church in the early 2nd century to emphasize its universal scope.
In the context of Christian ecclesiology, it has a rich history and several usages. In non-ecclesiastical use, it derives its English meaning directly from its root, and is currently used to mean the following: universal or of general interest; liberal, having broad interests, or wide sympathies; or inclusive, inviting and containing strong evangelism.
The term has been incorporated into the name of the largest Christian communion, the Catholic Church (also called the Roman Catholic Church). However, many other Christians use the term “Catholic” (sometimes with a lower-case letter “c”) to refer more broadly to the whole Christian Church or to all believers in Jesus Christ regardless of denominational affiliation.
The Eastern Orthodox, Oriental Orthodox, Anglicans, Lutherans, and some Methodists believe that their churches are “Catholic” in the sense that they are in continuity with the original universal church founded by the Apostles. However, each church defines the scope of the “Catholic Church” differently. For instance, the Roman Catholic, Eastern Orthodox, and Oriental Orthodox churches each maintain that their own denomination is identical with the original universal church, from which all other denominations broke away.
Almost all Christians who call themselves “Catholic” believe that bishops are considered the highest order of ministers within the Christian religion.
Along with unity, sanctity, and apostolicity, catholicity is considered one of Four Marks of the Church, in line with the Nicene Creed of 381: “I believe in one holy catholic and apostolic Church.” This tradition within Christianity is broadly known as Catholicism.