The word “catholic” is used in a number of ways among Christians today. Not surprisingly, it is rarely used correctly.
In speaking of the Catholic Church, our fathers were not using catholic as a brand name or denominational description (for there is—and has always been—only one, true Church). It also does not only apply to the Latin/Roman church today—the Orthodox Church is rightly termed the Catholic Church. These words should be seen as interchangeable, so long as they are being used in the right context.
Nor were our fathers using catholic to mean all-encompassing, as in “everything and everyone is welcome, no matter what one might think or believe on a particular doctrine or practice.” The Catholic faith is not a “lowest common denominator” faith, to be invoked in service of both denominationalism and schism. If catholic means “universal,” it means universal partly in the sense of “all that is true is found within.”
In other words, saying catholic is another way of saying orthodox—the full and whole faith of Christ and his apostles—a faith that is lacking nothing, and in need of nothing to be complete. The Church is catholic because it is the Body of Christ. The Church is catholic because it is united to Christ, with Truth himself as her head. And so, St. Ignatius of Antioch (A.D. 98–117) writes to the Smyrnæans (ch. 8) “wherever Jesus Christ is, there is the Catholic Church.”
Another way it means universal is that all of God’s people are found within. It is not a Church that ministers to only one nation, language, or people, but to all indiscriminately. As the “Catholic” Church, the Church is for everyone, and it is lacking nothing to make it “more” catholic in that sense.
To say that the Church is only for a specific culture, personality type, ethnic group, language, nation, political party, or anything else, is to deny that the Church is catholic. In Naturalis Historia, Roman naturalist Pliny the Elder (A.D. 23–79) writes of “clouds, thunder and lightning of all kinds” (2:38). The “lightning of all kinds” is, in Latin, catholica fulgurum; that is, “catholic” lightning.
The Orthodox Church has within her all kinds of people, all kinds of languages, all kinds of cultures, and all the truth of Christ and his apostles. This is why she is called catholic.