The term Roman Catholic first appeared in the English language in the 16th century to differentiate specific groups of Christians in communion with the Pope from others. It has continued to be widely used in the English language ever since, although its usage has changed over the centuries. It is now even used to distinguish different groups of Catholics who recognize the Pope, e.g., those who belong to the Western (i.e., Latin Rite) Church from those who belong to the Eastern Catholic Churches.
The Catholic Church consists of 23 autonomous Churches — one "Western" and 22 "Eastern" — governed by two sets of Codes of Canon Law. To refer to all 23 autonomous Churches together, official Church documents often use the term "Catholic Church" or, less frequently, the term "Roman Catholic Church". The usage that makes the term "Roman Catholic" mean members of the Latin Rite or Western Church to the exclusion of those who belong to the Eastern Catholic Churches does not appear in recent documents of the Holy See.
In popular usage, "Catholic Church" is usually understood to mean the same as "Roman Catholic Church". In some compound forms such as "Roman Catholic Worship", the term is used to differentiate Western practices.
The roots of the term Roman Catholic may be traced to the differences between English Catholics who remained loyal to the Pope from those who acknowledged the Elizabethan Settlement which re-established the Church of England’s independence from Rome in 1559.
The terms "Romish Catholic" and "Roman Catholic", along with "Popish Catholic", were probably originated in the English language by Protestants (who at times called themselves Protestant Catholics) who were not willing to concede the term Catholic to their opponents without qualification.
The reign of Elizabeth I of England at the end of the 16th century was marked by conflicts in Ireland. Those opposed to English rule forged alliances with those against Protestant reformation, making the term Roman Catholic almost synonymous with being Irish during that period, although that usage changed significantly over time.
Like the term Anglican, the term Roman Catholic came into widespread use in the English language only in the 17th century. The terms "Romish Catholic" and "Roman Catholic" were both in use in the 17th century and "Roman Catholic" was used in some official documents, such as those relating to the Spanish Match in the 1620s. There was, however, significant tension between Anglicans and Roman Catholics at the time (as reflected in the Test Act for public office). Even today, the Act of Settlement 1701 still prohibits Roman Catholics from becoming English monarchs.
The official and popular uses of the term Roman Catholic in the English language grew in the 18th century. Up to the reign of George III, Catholics in Britain who recognized the Pope as head of the Church had generally been designated in official documents as "Papists". In 1792, however, this phraseology was changed and in the Speech from the Throne, the term "Roman Catholic" was used.
By early 19th century, the term Roman Catholic had become well established in the English-speaking world. As the movement that led to Catholic Emancipation through the Catholic Relief Act of 1829 grew, many — though not all — Anglicans and Protestants generally began to accept that being a Roman Catholic was not synonymous with being disloyal to the British government. While believing that in the past the term Roman Catholic may have been synonymous with rebel, they held that it was by then as indicative of loyalty as membership in any other Christian denomination. The situation had been very different two centuries before, when Pope Paul V forbade English members of his Church from taking an oath of allegiance to King James I, a prohibition that not all of them observed.
Also in the 19th century, prominent Anglican theologians such as Palmer and Keble supported the Branch Theory, which viewed the universal Church as having three principal branches: Anglican, Roman and Eastern. The 1824 issue of The Christian Observer defined the term Roman Catholic as a member of the Roman Branch of the Church. By 1828, speeches in the English parliament routinely used the term Roman Catholic and referred to the "Holy Roman Catholic and Apostolic Church".
In the United States, the use of the term Roman Catholic and indeed the number of Roman Catholics began to grow only in the early 19th century, given that in 1790 there were only 100 Roman Catholics in New York and some 30,000 in the whole United States, with 29 priests. As the number of Roman Catholics in the United States grew rapidly from 150,000 to 1.7 million between 1815 and 1850 — mostly by way of immigration from Ireland and Germany — the clergy followed the people to serve them, and Roman Catholic parishes were established. The terms "Roman Catholic" and "Holy Roman Catholic" thus gained widespread use in the United States in the 19th century, both in popular usage and within official documents. In 1866 President Andrew Johnson attended a meeting of the Council of the Roman Catholic Church.
American Catholics, who by the year 1900 were 12 million people and had a predominantly Irish clergy, objected to what they considered the reproachful terms Popish and Romish and preferred the term Roman Catholic.
In the early 20th century, the use of the term Roman Catholic continued to spread within the United States and Canada, to refer to individuals, parishes and their schools. For instance, the 1915 Report of the Commissioner of Education of the United States had a specific section for "Roman Catholic Parish Schools". By 1918, legal proceedings in state supreme courts (from Delaware to Minnesota) and laws passed in the State of New York used the term "Roman Catholic parish".
By the middle of the 20th century the use of the term Roman Catholic was widely established in the United States and a 1957 survey by the United States Census Bureau determined that 25% of the US population applied the term Roman Catholic to themselves.
The term Roman Catholic is generally used on its own to refer to individuals, and in compound forms to refer to worship, parishes, festivals, etc. Its usage has varied, depending on circumstances. It is sometimes identified with one or other of the terms "Catholic", "Western Catholic" (equivalent to "Latin Catholic"), and "Roman-Rite Catholic".
In popular usage, "Catholic" usually means "Roman Catholic", a usage decried by some, including some Protestants. "Catholic" usually refers to members of any of the 23 constituent Churches, the one Western and the 22 Eastern. The same meaning is attributed also to "Roman Catholic" in documents of the Holy See, talks by Popes and in newspapers.
When used in a broader sense, the term Catholic is distinguished from "Roman Catholic" which has connotations of allegiance to the Bishop of Rome, i.e. the Pope. In this broader sense, "Catholic" also refers to many other Christians, especially Eastern Orthodox and Anglicans, but also to others, including Old Catholics and various independent Catholic Churches, who consider themselves to be living within the "catholic" tradition. They describe themselves as "Catholic", but not "Roman Catholic" and not under the authority of the Pope.
"...the individual becomes Eastern Catholic, not Roman Catholic".
Similarly the Catholic Faith Handbook for Youth states that
"...not all Catholics are Roman Catholics and there are other Catholic Churches",
using the term "Roman Catholic" to refer to Western Church members alone. The same distinction is made by writers in the Eastern Catholic Churches. That this view is not the only one, especially perhaps at popular level, is shown by the use of terms such as "Byzantine Roman Catholic" and "Maronite Roman Catholic" as self-identification by individuals or as the name of a church building. Additionally, in other languages, the usage varies significantly.
Although the Catholic Church has Western and Eastern branches, many, even Catholics, are unaware, or only dimly aware of this fact, partly because, outside the Middle East, Eastern Catholics are a small fraction of the total number of Catholics.
When referring to worship, the term Roman Catholic is at times used to refer to the "Roman Rite", which is not a church but a form of liturgy. The Roman Rite is distinct from the liturgies of the Eastern Catholic Churches and also from other Western liturgical rites such as the Ambrosian Rite, which have a much smaller following than the Roman Rite.
An example of this usage is provided in the book Roman Catholic Worship: Trent to today states:
"We use the term Roman Catholic Worship throughout to make it clear that we are not covering all forms of Catholic worship. There are a number of Eastern Rite churches that can justly claim the title Catholic, but many of the statements we make do not apply to them at all.".
Compared to the Roman Rite, the other Western liturgical rites have little following. Hence, the Vatican department that deals with forms of worship (including music) in the Western Church often issues documents that deal only with the Roman Rite.  Any involvement by the Holy See in questions of Eastern liturgies is handled by a different department.
Some of the writers who draw a contrast between "Roman Catholics" and "Eastern Catholics" may perhaps be distinguishing Eastern Catholics not from Latin or Western Catholics in general, but only from those (the majority of Latin Catholics) who use the Roman liturgical rite. Adrian Fortescue explicitly made this distinction, saying that, just as "Armenian Catholic" is used to mean a Catholic who uses the Armenian rite, "Roman Catholic" could be used to mean a Catholic who uses the Roman Rite. In this sense, he said, an Ambrosian Catholic, though a member of the Latin or Western Church, is not a "Roman" Catholic. He admitted, however, that this usage is uncommon.
When the term "Roman Catholic" is used as part of the name of a parish it usually indicates that it is a Western parish that follows the Roman Rite in its liturgy, rather than, for instance, the less common Ambrosian Rite, e.g. St. Dominic Roman Catholic Church, Oyster Bay, New York. The shorter term "Catholic" may also appear in parish names and "Roman Catholic" sometimes even appears in the compound name of Eastern Catholic parishes, e.g. St. Mary's Byzantine Roman Catholic Church.
All Catholic parishes are part of an ecclesiastical jurisdiction, usually a diocese (called an eparchy in the canon law of the Eastern Catholic Churches). These jurisdictions are usually grouped in ecclesiastical provinces, headed by a metropolitan archdiocese. All dioceses and similar jurisdictions — Eastern and Western — come under the authority of the Pope.. The term "Roman Catholic archdiocese" is formally used to refer to both Western and Eastern Churches. As of January 2009, there were 630 Roman Catholic archdioceses, Western and Eastern.
The terms "Catholic Church" and "Roman Catholic Church" are names for the entire church that describes itself as "governed by the successor of Saint Peter and by the bishops in communion with him". In its formal documents and pronouncements the church most often refers to itself as the Catholic Church or simply the Church. In its relations with other churches, it frequently uses the name "Roman Catholic Church", which it uses internally also, though less frequently. Some writers such as Kenneth Whitehead and Patrick Madrid argue that the only proper name for the Church is "the Catholic Church".
Some Catholic writers such as Kenneth Whitehead argue that the proper name of the Church is the "Catholic Church" rather than the "Roman Catholic Church". Kenneth Whitehead and Patrick Madrid argue that the term "Roman Catholic" has Anglican origins and that the term is used to leave open the possibility that there are other "Catholic" churches.
The name "Roman Catholic Church" is occasionally used by popes, bishops, other clergy and laity, who do not see it as opprobrious or having the suggested overtone. The use of "Roman", "Holy" and "Apostolic" are accepted by the Church as descriptive names. Some US states and the country of England require the Church to use the legal name "Roman Catholic Church". At the time of the 16th-century Reformation, the Church itself "claimed the word catholic as its title over Protestant or Reformed churches". It believes that it is the one, holy, catholic, and apostolic Church.
Throughout the years, in various instances, official Church documents have used both the terms "Catholic Church" and "Roman Catholic Church" to refer to the worldwide Church as a whole, including Eastern Catholics, as when Pope Pius XII taught in Humani Generis that "the Mystical Body of Christ and the Roman Catholic Church are one and the same thing". However, some Easterners, though in communion with the Bishop of Rome, apply the adjective "Roman" to the Latin or Western Church alone. Representatives of the Catholic Church are at times required to use the term "Roman Catholic Church" in certain dialogues, especially in ecumenical milieu, since some Protestants consider themselves authentic instances of Catholic faith.
In the 21st century, the three terms Catholic Church, Roman Catholic Church and the Holy Roman Catholic Church continue to appear in various books and publications, and scholarly debates on the proper form of reference to the Catholic Church within specific contexts continue. For instance, the Catechism of the Catholic Church does not contain the term "Roman Catholic Church", referring to the Church only by names such as "Catholic Church" (as in its title), while the Advanced Catechism Of Catholic Faith And Practice states that the term Roman is used within the name of the Church to emphasize that the center of unity of the Church is the Roman See.
There is controversy about the name "Roman Catholic Church" because of its use by some outside the Church to suggest that the Church in Rome is only one part of the One, Holy, Catholic and Apostolic Church. This argument is linked especially with the Anglican Branch Theory, (i.e., that the Church in communion with the Pope is only one branch of a divided Catholic Church, of which the Eastern Orthodox Church and Anglicanism are the other two branches).
In 1864, the Holy Office rejected the Branch Theory, affirming in a letter written to the English Bishops that the Roman Church is not just a part of the Catholic Church and stating that "there is no other Catholic Church except that which is built on the one man, Peter ...." In 1870, English bishops attending the First Vatican Council raised objections to the expression "Holy Roman Catholic Church" which appeared in the schema (the draft) of the Council's Dogmatic Constitution on the Catholic Faith. These bishops proposed that the word "Roman" be omitted out of concern that use of the term "Roman Catholic" would lend support to proponents of the Branch Theory. While the Council overwhelmingly rejected this proposal, the text was finally modified to read "The Holy Catholic Apostolic and Roman Church".[note 1]
The Second Vatican Council did not use the term "Roman Catholic Church", and in one important passage replaced it with an equivalent phrase, "the Catholic Church, which is governed by the successor of Peter and by the bishops in union with that successor", while also giving in a footnote a reference to two earlier documents in which the word "Roman" was used explicitly.
The Second Vatican Council's dogmatic constitution Lumen gentium declares that the phrase "Roman Church" has been applied in the Tridentine Profession of Faith to the Church itself, the Church "governed by the successor of Saint Peter and by the bishops in communion with him". Even as far back as 1208 the adjective "Roman" was applied to the Church "outside which we believe that no one is saved".
While the phrase "Roman Catholic Church" does not appear in the Catechism of the Catholic Church, the Advanced Catechism of Catholic Faith and Practice states that the term "Roman" is used within the name of the Church to emphasize that the centre of unity of the Church is the Roman See.
Some Eastern-rite Catholics reject the description of themselves as "Roman", even though they're a part of the Catholic Church. Others are proud to call themselves Roman Catholics, and "Roman Catholic" sometimes even appears in the compound name of Eastern Catholic parish churches, e.g. St. Mary's Byzantine Roman Catholic Church.