Catholicism has two main ecclesiastical meanings, described in Webster's Dictionary as: a) "the whole orthodox Christian church, or adherence thereto"; and b) "the doctrines or faith of the Roman Catholic church, or adherence thereto."
The term comes from the Greek adjective καθολικός -ή -όν (katholikos), meaning "general" or "universal". In Greek, the word for "church" is feminine and takes the feminine form of the adjective, viz.: ἡ Καθολικὴ Ἐκκλησία.
Yet more explicit was the manner in which Saint Cyril of Jerusalem (circa 315-386) used the term "catholic Church" precisely to distinguish this Church from heretical "Churches". He urged: "If ever thou art sojourning in cities, inquire not simply where the Lord's House is (for the other sects of the profane also attempt to call their own dens houses of the Lord), nor merely where the Church is, but where is the Catholic Church. For this is the peculiar name of this Holy Church, the mother of us all, which is the spouse of our Lord Jesus Christ, the Only-begotten Son of God" (Catechetical Lectures, XVIII, 26).
The word Catholic has been used ever since to describe the genuine one original Church founded by Christ and the Apostles. The word appears in the main Christian creeds (formal definitions of belief), notably the Apostles' Creed and the Nicene Creed. As such, many Christians (and denominations) see themselves as "catholic". They fall into two groups:
Christians of most denominations, including most Protestants, affirm their faith in "One Holy Catholic and Apostolic Church". For Protestants, most of whom consider themselves to be spiritual descendants (category 2, above), this affirmation refers to their belief in the ultimate unity of all churches under one God and one Saviour, rather than in one visibly unified institutional church (category 1, above). In this usage catholic is sometimes written with a lower-case "c". The Western Apostles' Creed, stating "I believe in...the holy catholic church..." (sometimes capitalised), is thus recited in Protestant worship services (with the notable exception of German Lutherans). The Nicene Creed likewise declares belief in "one holy catholic and apostolic Church".
The AD 431 Council of Ephesus, the Third Ecumenical council, was chiefly concerned with Nestorianism. Nestorianism emphasized the distinction between the humanity and divinity of Jesus and taught that the Virgin Mary gave birth not to God but only to the man, Jesus Christ. This Council rejected Nestorianism and affirmed that humanity and divinity were inseparable in the one person Jesus Christ, and that his mother, the Virgin Mary, is thus Theotokos, God-bearer, Mother of God. The first great rupture in the Church followed this Council)\\. Those who refused to accept the Council's ruling were largely Persian and are represented today by the Assyrian Church of the East and related Churches..
The next major break was after the Council of Chalcedon (AD 451). This Council repudiated Eutychian Monophysitism which states that the divine nature completely subsumed the human nature in Christ. This Council declared that Christ, though one person, exhibited two natures "without confusion, without change, without division, without separation" and thus is both fully God and fully human. The Alexandrian Church rejected the terms adopted by this Council. These Christians are now often referred to as Ancient Oriental Churches or the Oriental Orthodox Communion.
The next major rift within Christianity was in the 11th century. Doctrinal disputes, as well as conflicts between methods of Church government, and the evolution of separate rites and practices, precipitated a split in AD 1054 that divided the Church, this time between a "West" and an "East". England, France, the Holy Roman Empire, Scandinavia, and much of the rest of Western Europe were in the Western camp, and Greece, Russia and many of other Slavic lands, Anatolia, and the Christians in Syria and Egypt who accepted the Council of Chalcedon made up the Eastern camp. This division is called the Great Schism. The most recent major division in the Church occurred in the 16th century with the Protestant Reformation, after which many parts of the Western Church rejected the teachings of the Roman Catholic Church and became known as "Protestant".
All of the preceding groups, excluding some Protestants, consider themselves to be fully and completely Catholic. All of them claim to be either part of the Catholic Church or the only Catholic Church.
This Church hardly ever uses the name "Roman Catholic Church" for itself, except in its relations with other Christian groups. Even in those relations, "Catholic Church" may also appear, as in some documents drawn up in common with the Lutheran World Federation and the Assyrian Church of the East. On the other hand, the Church has in fact applied the adjective "Roman" to itself in its entirety even in some internal documents, such as the Dogmatic Constitution de fide catholica of the First Vatican Council, which was attended by Eastern as well as Western bishops. When it does apply the adjective "Roman" to itself, it understands this word only as pointing to the centrality for it of the see of Rome, with which all its members, laity and clergy alike, are necessarily in Full communion. Outsiders, in contrast, considering the use of the name "Catholic Church" by this Church to be contentious, use the term "Roman Catholic Church" to imply that it is only the "Roman" section of some larger, perhaps abstract, entity that they call the Catholic Church and that, in their view, also includes other sections not in communion with Rome, a usage that members of the Church in question in turn see as contentious.
Frequently enough, some members of this Church, especially those of Eastern Rite, apply the term "Roman Catholic Church" not, as in the Church's official documents, to the Church as a whole, but only to its Latin Rite component. Unlike the outsiders just mentioned, they consider communion with the see of Rome essential for all members of the Catholic Church.
The Anglican Communion is in practice divided into two wings, "High Church Anglicans" also called the Anglo-Catholics and "Low Church Anglicans" also known as the Evangelical wing. Though all elements within the Anglican Communion recite the same creeds, Low Church Anglicans regard the word Catholic in the ideal sense given above, while High Church Anglicans treat it as a name of Christ's church which they consider to embrace themselves together with the Roman Catholic and several Orthodox Churches.
Anglo-Catholicism maintains similarities to the Latin Rite of Roman Catholicism and related spirituality, including a belief in seven sacraments, Transubstantiation as opposed to Consubstantiation, devotion to the Virgin Mary and saints, the description of their ordained clergy as "priests" - addressed as "Father" - the wearing of vestments in church liturgy, sometimes even the description of their Eucharistic celebrations as "Mass". The development of the Anglo-Catholic wing of Anglicanism occurred largely in the nineteenth century and is strongly associated with the Oxford Movement. Two of its leading lights, John Henry Newman and Henry Edward Manning, both ordained Anglican clergymen, ended up joining the Roman Catholic Church, becoming cardinals.
The several churches of Eastern Orthodoxy and Oriental Orthodoxy each consider themselves to be the universal and true Catholic Church, and typically regard the other of these families and the Western Catholics as heretical and as having left the One Holy Catholic, and Apostolic Church. The patriarchs of these Eastern Orthodox and Oriental Orthodox Churches are autocephalous hierarchs, which roughly means that each of them is independent of the direct oversight of another bishop (although still subject, according to their distinct traditions, either to the Synod of bishops of each one's jurisdiction, or only to a common decision of the patriarchs of their own communion). They are willing to concede a primacy of honor to the Petrine See, but not of authority.
Baptism is the first and basic sacrament of Christian initiation. Catholics consider baptism conferred in most Christian denominations "in the name of the Father and of the Son and of the Holy Spirit" (cf. Matthew 28:19) to be valid, since the effect is produced through the sacrament, independently of the faith of the minister, though not of the minister's intention. Baptism, as stated in the Nicene Creed is "for the remission of sins", not only personal sins, but also Original sin, which it remits even in infants who have committed no personal sins. Expressed positively, remission of sins means bestowal of the sanctifying grace by which the baptized person shares the life of God.
Confirmation or Chrismation is the second sacrament of Christian initiation. It is conferred by the laying on of hands and anointing, together with a special consecratory prayer. Through it, the gift of the Holy Spirit conferred in baptism is "strengthened and deepened" (see Catechism of the Catholic Church §1303). Its "originating" minister is a validly consecrated bishop; if a priest (a "presbyter") confers the sacrament - as is done ordinarily in Eastern Churches and in particular cases in Western - the link with the higher order is indicated by the use of chrism (also called myrrh) blessed by a bishop (in an Eastern Orthodox Church, by the patriarch]]). In the East the sacrament is administered immediately after baptism. In the West administration came to be postponed until the recipient's early adulthood; but in view of the earlier age at which children are now admitted to reception of the Eucharist, it is more and more restored to the traditional order and administered before giving the third sacrament of Christian initiation.
The Eucharist is the sacrament (the third of Christian initiation) by which Catholics partake of the Body and Blood of Jesus Christ and participate in his one sacrifice. The bread and wine used in the rite are, in Catholic faith, considered to be transformed in all but appearance into the Body and Blood of Christ, a change that is commonly called Transubstantiation.
Penance and Reconciliation are names given to the first of two sacraments of healing, which is also called the sacrament of conversion, of confession, and of forgiveness (Catechism of the Catholic Church, 1423-1424). It is the sacrament of spiritual healing of a baptized person from the distancing from God involved in sins committed. It involves four elements: the penitent's contrition for sin (without which the rite does not have its effect), confession to a priest (it may be spiritually helpful to confess to another, but only a priest has the power to administer the sacrament), absolution by the priest, and satisfaction. In early Christian centuries, the fourth element was quite onerous and generally preceded absolution, but now it usually involves a simple task (in some traditions called a "penance") for the penitent to perform, to make some reparation and as a medicinal means of strengthening against further temptation.
Anointing of the Sick is the second sacrament of healing. In it those who are suffering a serious physical illness are anointed by a priest with oil blessed specifically for that purpose. "Seriously sick" does not necessarily mean "in immediate danger of death". In past centuries, when such a restrictive interpretation was customary, the sacrament came to be known as "Extreme Unction", i.e. "Final Anointing". It was then conferred only as one of the "Last Rites". The other "Last Rites" are Confession (if the dying person is physically unable to confess, at least absolution, conditional on the existence of contrition, is given), and the Eucharist, which when administered to the dying is known as "Viaticum", a word whose original meaning in Latin was "provision for a journey".
Holy Orders is the sacrament by which one becomes a bishop, a priest or a deacon. Only a bishop may administer this sacrament. Ordination as a bishop confers the fulness of the sacrament, making the bishop a member of the body that has succeeded to that of the Apostles, and giving him the mission to teach, sanctify and guide, along with the care of all the Churches. Ordination as a priest configures the priest to Christ the Head of the Church and the one essential Priest, empowering him, as the bishops' assistant, to celebrate divine worship, especially the Eucharist. Ordination as a deacon configures the deacon to Christ the Servant of All, placing him at the service of the Church, especially in the fields of the ministry of the word, divine worship, pastoral guidance and charity.
Holy Matrimony, like Holy Orders, is a sacrament that consecrates for a particular mission in building up the Church, providing grace for accomplishing that mission.