The Church is also called the House of Prayer in fulfillment of the Prophecy of Isaias:
"The children of the stranger that join themselves to the Lord, to worship Him, and to love His Name, and to be His servants: every one that keepeth the Sabbath from profaning it and that holdeth fast to My covenant: even them I will bring into My holy mountain and make them joyful in My house of prayer; their burnt offerings and their victims shall please Me upon Mine altar: for My house shall be called the house of prayer for all nations." (Prophecy of Isaias 56)
In Latin "House of Prayer" is "Domus Orationis," and from this expression we have two names for church, "Dome" and "Oratory." The church was also called the "House of God" as well as the "House of Prayer," and thus the chief church at last became known as the "House" or "Domus." This appears in English as "Dome," which is popularly applied to a rounded structure raised above the roof. In Germany, however, "Dom" means the Cathedral, and in Italy "Duomo" has the same signification. Thus we have the Koelner Dom or Cathedral of Cologne, and the Duomo or Cathedral of Milan. Byron uses the English word in this sense in his description of Saint Peter's, Rome:
"But lo! the dome the vast and wondrous dome,
To which Diana's marvel was a cell.
Christ's mighty shrine above his martyr's tomb!
I have beheld the Ephesian's miracle
Its columns strew the wilderness, and dwell
The hyena and the jackal in their shade;
I have beheld Sophia's bright roofs swell
Their glittering mass in the sun, and have survey'd
Its sanctuary the while the usurping Moslem pray'd;
But thou, of temples old, or altars new,
Standest alone with nothing like to thee
Worthiest of God, the holy and the true.
Since Zion's desolation, when that He
Forsook his former city, what could be,
Of earthly structures in his honor piled,
Of a sublimer aspect? Majesty,
Power, Glory, Strength, and Beauty all are aisled
In this eternal ark of worship undetiled."
From the Latin word for prayer, "Oratio," we get the term "Oratory." An oratory is usually a small room in a private house set aside for private devotions; but the Sacrifice cannot be offered therein except with special permission and under many restrictions. A room, how ever, permanently set apart for worship and open to the people is known as a public oratory. The places of worship in convents, colleges, institutions and the like come under this category. They are practically little churches, and, as far as the offering of the Sacrifice goes, they are, with a very slight difference, on the same level as other churches. The common name for such oratories is "Chapel." "Capella" means a little cape or cloak, and in particular the cloak of Saint Martin, Bishop of Tours, who died about the year 400. The French kings considered this cloak a very precious relic, and they built an oratory in which it was preserved. By the figure of speech referred to before, the oratory itself was called a Capella, or Chapel, and the name spread to structures of the same nature, especially to those in which the relics of the saints were preserved. It is now used for the subordinate structures attached to large churches and also for separate churches erected at some distance from the Parish Church for the convenience of the parish when the district is extensive. In Ireland the word Chapel is used to distinguish a Catholic from Protestant church. The reformers stole all the Catholic churches in that country, so that when the Catholics built new churches of their own these were really chapels. The people have retained the name as a protest against spoliation, because it reminds them that the churches which their forefathers built were unjustly taken from them.
For three hundred years the Catholic Church was persecuted by the pagan emperors of Rome. In the year 313 Constantine proclaimed toleration by the edict of Milan. The Church was now at liberty to build great public structures for her Liturgy. She did not take the old pagan temples for her model, because, though large externally, they were narrow and uncomfortable within, and therefore not suited for congregational purposes. There were, however, in Rome large and spacious buildings used as courts of justice, halls of public meeting and merchants exchanges. In Athens justice was dispensed by an official who was known as the King-Ruler. The building in which he held his court was called the " Kingly" building. This word was borrowed by the Romans and applied to those great halls in which the courts sat. Hence they are known as Basilicas, because Basilica is the Latin form of the Greek word "Basilike", which signifies "Kingly" or "Royal." When the Christians were permitted to worship openly they built Basilicas for churches. However, in naming them, they naturally substituted for the idea of an earthly king and judge the idea of the King of Heaven and the Judge of the living and of the dead. In some places Basilica was used as a synonym for church, especially for a large church or cathedral. As a title of honor and privilege it is applied to thirteen churches in the City of Rome, five of which are called the greater Basilicas and eight the lesser Basilicas. Outside of Rome there are a few churches which enjoy this distinction for instance, the Church of Saint Francis at Assisi and the Church at Lourdes.
During the persecution a person who gave up his life rather than deny the faith was called a martyr. "Martyr" is a Greek word which means a "witness," and martyrs were witnesses that the faith of Christ was true. The place where the martyrdom took place was called the "Martyrium," which name was also applied to the place where the martyr's remains were buried. Martyrium was translated into Latin by "Confessio," which means "witnessing," or confession. In order to honor the martyrs and keep their memory in the minds of the faithful Mass was said on their tombs and little chapels were built over their remains. These structures were also called "Confessions" and quite naturally "Memorials." When the persecutions ceased great Basilicas were built over the Confessions of the most famous martyrs, as for instance, Saint Peter's. The Confession was kept intact, and the high altar was erected over it. We may often see descriptions of the Pope going down under the high altar to the Confession of Saint Peter to pray. He is repairing to the same humble tomb which was built by the poor of Rome over the poor fisherman who, nearly nineteen centuries ago, confessed in his blood the Master he had denied by his mouth. Besides the cemeteries with tombs above ground, the Christians used long galleries, or tunnels, which had been excavated in the country around Rome for burial places, and also for meeting places. They arc called "Catacombs," and were often of great extent, having long, winding streets, large open spaces, churches, tombs, all hewn out of the soft rock. Being richly decorated with pictures and inscriptions, they are even to this day mines of information concerning the belief and practices of our fathers in the faith. Thus originally all churches were erected over the tombs or in the tombs of the martyrs, and it is the law even to this day that every church must contain within it some relic of the saints.
The anniversary of the day on which the martyr died was kept as a great feast; first at the memorial and later in the larger churches built over it. Such celebrations fixed the names of particular martyrs on particular churches. Thus we have Saint Paul's, Saint Peter's, Saint Agnes , Saint Cecilia's. These saints were called the "Patrons" of the churches and also "Titulars." "Titulars" because they gave the church its "title" and "Patrons" because they took the place under their "Patronage," or particular charge. In old Rome the great Patrician families had a number of followers or retainers who did them service, and whom the Patricians defended and protected in turn. The protector was called a patron, and his follower was called a client. In Rome, then, the Christians looked upon themselves as the clients or followers of the martyr, and he was to them a patron, a friend in God's court. In later days churches were named after saints who were not martyrs, and also after mysteries of faith, as, for example: Holy Trinity Church, the Church of the Annunciation, Saint Patrick's, and so on.
About the fourth century a great movement took place in Christendom. Every where men and women went out of the cities and retired into the uninhabited wastes, and tried to save their souls in solitude, in work and in prayer. Those men were called "monks," from a Greek word which means "alone." The little houses in which they lived were called "cells," from a Latin word "cella," meaning "concealed." Saint Patrick, who was a monk, brought this state of life into Ireland, and all over the country were to be found solitaries in their little cells. They were not left solitary long, for people came to them for instruction, and settled in their vicinity. A church was, of course, a necessity, and this church was called the cell of the founder of the settlement. Thus, even when the monks had disappeared, and great towns had taken the place of their rude huts, and stately churches were built on the site of the original "Cella," the old title remained. The term "Kil," which begins so many names of places in Ireland, is simply "cella," pronounced with the "c" hard, as it was in Saint Patrick's time. Thus, Kilkenny is the Cella or Church of Saint Kenny; Kilbride is the Church of Saint Bride or Brigid; Kildare is the Church of the Oak; Kilmore is the Great Church. This style of naming places and churches is also to be found in Scotland, where it was brought out of Ireland by the apostle of that country, Saint Columkille, whose name in Latin is "Columba cellae," but in English "The Dove of the Church." In California the churches erected by the Franciscan missionaries in Spanish times are known as "Mission's."
- taken from The Mass, by Father Peter Christopher Yorke