Catholic Rites and Churches


A Rite represents an ecclesiastical, or church, tradition about how the sacraments are to be celebrated. Each of the sacraments has at its core an essential nature which must be satisfied for the sacrament to be confected or realized. This essence - of matter, form and intention - derives from the divinely revealed nature of the particular sacrament. It cannot be changed by the Church. Scripture and Sacred Tradition, as interpreted by the Magisterium, tells us what is essential in each of the sacraments (2 Thes. 2:15). 

When the apostles brought the Gospel to the major cultural centers of their day the essential elements of religious practice were inculturated into those cultures. This means that the essential elements were clothed in the symbols and trappings of the particular people, so that the rituals conveyed the desired spiritual meaning to that culture. In this way the Church becomes all things to all men that some might be saved (1 Cor. 9:22).

There are three major groupings of Rites based on this initial transmission of the faith, the Roman, the Antiochian (Syria) and the Alexandrian (Egypt). Later on the Byzantine derived as a major Rite from the Antiochian, under the influence of St. Basil and St. John Chrysostom. From these four derive the over 20 liturgical Rites present in the Church today.


A Church is an assembly of the faithful, hierarchically ordered, both in the entire world -  the Catholic Church, or in a certain  territory - a particular Church. To be a sacrament (a sign) of the Mystical Body of Christ in the world, a Church must have both a head and members (Col. 1:18).  The sacramental sign of Christ the Head is the sacred hierarchy - the bishops, priests and deacons (Eph. 2:19-22). More specifically, it is the local bishop, with his priests and deacons gathered around and assisting him in his office of teaching, sanctifying and governing (Mt. 28:19-20; Titus 1:4-9). The sacramental sign of the Mystical Body is the Christian faithful. Thus the Church of Christ is fully present sacramentally (by way of a sign) wherever there is a sign of Christ the Head, a bishop and those who assist him, and a sign of Christ's Body, Christian faithful. Each diocese is therefore a particular Church.

The Church of Christ is also present sacramentally in ritual Churches that represent an ecclesiastical tradition of celebrating the sacraments. They are generally organized under a Patriarch, who together with the bishops and other clergy of that ritual Church represent Christ the Head to the people of that tradition. In some cases a Rite is completely coincident with a Church. For example, the Maronite Church with its Patriarch has a Rite not found in any other Church. In other cases, such as the Byzantine Rite, several Churches use the same or a very similar liturgical Rite. For example, the Ukrainian Catholic Church uses the Byzantine Rite, but this Rite is also found in other Catholic Churches, as well as the Eastern Orthodox Churches not in union with Rome.

Finally, the Church of Christ is sacramentally present in the Universal or Catholic Church spread over the entire world. It is identified by the sign of Christ our Rock, the Bishop of Rome, Successor of St. Peter (Mt. 16:18). To be Catholic particular Churches and ritual Churches must be in communion with this Head, just as the other apostles, and the Churches they founded, were in communion with Peter (Gal. 1:18). Through this communion with Peter and his successors the Church becomes a universal sacrament of salvation in all times and places, even to the end of the age (Mt. 28:20).

Western Rites and Churches
mmediately subject to the Supreme Pontiff as Patriarch of the West


(also called Latin)
The Church of Rome is the Primatial See of the world and the Patriarchal See of Western Christianity. Founded by St. Peter in 42 AD it was consecrated by the blood of Sts. Peter and Paul during the persecution of Nero (63-67 AD). It has maintained a continual existence since then and is the source of a family of Rites in the West. Considerable scholarship (such as that of Fr. Louis Boyer in Eucharist) suggests the close affinity of the Roman Rite proper with the Jewish prayers of the synagogue, which also accompanied the Temple sacrifices. While the origin of the current Rite, even in the reform of Vatican II, can be traced directly only to the 4th century, these connections point to an ancient apostolic tradition brought to that city that was decidedly Jewish in origin.

After the Council of Trent it was necessary to consolidate liturgical doctrine and practice in the face of the Reformation. Thus, Pope St. Pius V imposed the Rite of Rome on the Latin Church (that subject to him in his capacity as Patriarch of the West), allowing only smaller Western Rites with hundreds of years of history to remain. Younger Rites of particular dioceses or regions ceased to exist.


Roman Rite (Tridentine Mass) - The sacramental rites according to the forms in use prior to the Second Vatican Council. This is the Mass that our beloved saints of the Catholic Church attended and assisted at (excluding Eastern Rite saints). Much of its prayers (especially within the Canon) originated from Our Lord and the Apostles. Further extension of the Mass and its rubrics was guided by the Holy Ghost and presented by Holy Mother Church. The Mass was considered complete in 1570 A.D. by Pope St. Pius V.

"New " Roman Rite -  The current Roman Rite is that of the 1969 Missale Romanum. This "Mass" is strikingly similar to Protestant services. In fact, six Protestant ministers served as advisors at Vatican II. The new Mass was an extension of that council and the fruits have been disastrous. Since this Mass has been introduced, the Catholic Church has seen a decline that it has never see before in the history of the Catholic Church. The "New" Roman Rite is in direct contradiction of Pope Pius V's Quo Primum encyclical. 
Mozarabic - The Rite of the Iberian peninsula (Spain and Portugal) known from at least the 6th century, but probably with roots to the original evangelization. Beginning in the 11th century it was generally replaced by the Roman Rite, although it has remained the Rite of the Cathedral of the Archdiocese of Toledo, Spain, and six parishes which sought permission to adhere to it. Its celebration today is generally semi-private.
Ambrosian - The Rite of the Archdiocese of Milan, Italy, thought to be of early origin and probably consolidated, but not originated, by St. Ambrose. It continues to be celebrated in Milan, though not by all parishes.
Bragan - Rite of the Archdiocese of Braga, the Primatial See of Portugal, it derives from the 12th century or earlier. It continues to be of occasional use.
Dominican - Rite of the Order of Friars Preacher (OP), founded by St. Dominic in 1215.
Carmelite - Rite of the Order of Carmel, whose modern foundation was by St. Berthold c.1154.
Carthusian - Rite of the Carthusian Order founded by St. Bruno in 1084. 

Eastern Rites and Churches

They have their own hierarchy distinct from the Latin Rite, system of governance (synods) and general law, the Code of Canons for the Eastern Churches. The Supreme Pontiff exercises his primacy over them through the Congregation for the Eastern Churches.

The Church of Antioch in Syria (on the Mediterranean coast) is considered an apostolic see by virtue of having been founded by St. Peter. It was one of the ancient centers of the Church, as the New Testament attests, and is the source of a family of similar Rites using the ancient Syriac language (the Semitic dialect used in Jesus' time and better known as Aramaic). Its Liturgy is attributed to St. James and the Church of Jerusalem.

Maronite - Never separated from Rome. Maronite Patriarch of Antioch. The liturgical language  is Aramaic. The 3 million Maronites are found in Lebanon (origin), Cyprus, Egypt, Syria, Israel, Canada, US, Mexico, Brazil, Argentina and Australia.
Syriac - Syrian Catholics who returned to Rome in 1781 from the monophysite heresy. Syriac Patriarch of Antioch. The 110,000 Syrian Catholics are found in Syria, Lebanon, Iraq, Egypt, Canada and the US.
Malankarese - Catholics from the South of India evangelized by St. Thomas, uses the West Syriac liturgy. Reunited with Rome in 1930. Liturgical languages today are West Syriac and Malayalam. The 350,000 Malankarese Catholics are found in India and North America.

Chaldean - Babylonian Catholics returned to Rome in 1692 from the Nestorian heresy. Patriarch of Babylon of the Chaldeans. Liturgical languages are Syriac and Arabic. The 310,000 Chaldean Catholics are found in Iraq, Iran, Syria, Lebanon, Egypt, Turkey and the US.
Syro-Malabarese - Catholics from Southern India using the East Syriac liturgy. Returned to Rome in the 16th century from the Nestorian heresy. Liturgical languages are Syriac and Malayalam. Over 3 million Syro-Malabarese Catholics can be found in the state of Kerela, in SW India.


The Church of Constantinople became the political and religious center of the eastern Roman Empire after the Emperor Constantine built a new capital there (324-330) on the site of the ancient town of Byzantium. Constantinople developed its own liturgical rite from the Liturgy of St. James, in one form as modified by St. Basil, and in a more commonly used form, as modified by St. John Chrysostom. After 1054, except for brief periods of reunion, most Byzantine Christians have not been in communion with Rome. They make up the Orthodox Churches of the East, whose titular head is the Patriarch of Constantinople. The Orthodox Churches are mostly auto-cephalous, meaning self-headed, united to each other by communion with Constantinople, which exercises no real authority over them. They are typically divided into Churches along nation lines. Those that have returned to communion with the Holy See are represented among the Eastern Churches and Rites of the Catholic Church.

Considered either its own Rite or an older version of the Byzantine. Its exact form is not used by any other Byzantine Rite. It is composed of Catholics from the first people to convert as a nation, the Armenians (N.E. of  Turkey), and who returned to Rome at the time of the Crusades. Patriarch of Cilicia of the Armenians. The liturgical language is classical Armenian. The 350,000 Armenian Catholics are found in Armenia, Syria, Iran, Iraq, Lebanon, Turkey, Egypt, Greece, Ukraine, France, Romania, United States and Argentina. Most Armenians are Orthodox, not in union with Rome.

Albanian - Albanian Christians, numbering only 1400 today, who resumed communion with Rome in 1628. Liturgical language is Albanian. Most Albanian Christians are Albanian Orthodox.
Belarussian/Byelorussian - Unknown number of Belarussians who returned to Rome in the 17th century. The liturgical language is Old Slavonic. The faithful can be found in Belarus, as well as Europe, the Americas and Australia.
Bulgarian - Bulgarians who returned to Rome in 1861. Liturgical language is Old Slavonic. The 20,000 faithful can be found in Bulgaria. Most Bulgarian Christians are Bulgarian Orthodox.
Czech - Czech Catholics of Byzantine Rite organized into a jurisdiction in 1996.
Krizevci - Croatian Catholics of Byzantine Rite who resumed communion with Rome in 1611. The liturgical language is Old Slavonic.  The 50,000 faithful can be found in Croatia and the Americas. Most Croatians are Roman (Rite) Catholics.
Greek - Greek Christians who returned to Rome in 1829. The liturgical language is Greek. Only 2500 faithful in Greece, Asia Minor (Turkey) and Europe. Greek Christians are almost all Orthodox, whose Patriarch is the Orthodox Patriarch of Constantinople.
Hungarian - Descendants of Ruthenians who returned to Rome in 1646. The liturgical languages are Greek, Hungarian and English. The 300,000 faithful are found in Hungary, Europe and the Americas.
Italo-Albanian - Never separated from Rome, these 60,000 Byzantine Rite Catholics are found in Italy, Sicily and the Americas. The liturgical languages are Greek and Italo-Albanian.
Melkite - Catholics from among those separated from Rome in Syria and Egypt who resumed Communion with Rome at the time of the Crusades. However, definitive union only came in the 18th century. Melkite Greek Patriarch of Damascus. Liturgical languages are Greek, Arabic, English, Portuguese and Spanish. The over 1 million Melkite Catholics can be found in Syria, Lebanon, Jordan, Israel, Canada, US, Mexico, Brazil, Venezuela, Argentina and Australia.
Romanian - Romanians who returned to Rome in 1697. The liturgical language is Romanian. There are over 1 million Romanian Catholics in Romania, Europe and the Americas. Most Romanian Christians are Romanian Orthodox.
Russian - Russians who returned to communion with Rome in 1905. The liturgical language is Old Slavonic. An unknown number of the faithful in Russia, China, the Americas and Australia. Most Russian Christians are Russian Orthodox, whose Patriarch is the Orthodox Patriarch of Moscow.
Ruthenian - Catholics from among those separated from Rome in Russia, Hungary and Croatia who reunited with Rome in 1596 (Brest-Litovsk) and 1646 (Uzhorod).
Slovak - Byzantine Rite Catholics of Slovakian origin numbering 225,000 and found in Slovakia and Canada.
Ukrainian - Catholics from among those separated from Rome by the Greek Schism and reunited about 1595. Patriarch or Metropolitan of Lviv. Liturgical languages are Old Slavonic and the vernacular. The 5.5 million Ukrainian Catholics can be found in Ukraine, Poland, England, Germany, France, Canada, US, Brazil, Argentina and Australia. During the Soviet era Ukrainian Catholics were violently forced to join the Ukrainian Orthodox Church. Their hierarchy, which continued to exist outside the homeland, has since been re-established in Ukraine.


The Church of Alexandria in Egypt was one of the original centers of Christianity, since like Rome and Antioch it had a large Jewish population which was the initial object of apostolic evangelization. Its Liturgy is attributed to St. Mark the Evangelist, and shows the later influence of the Byzantine Liturgy, in addition to its unique elements.

Coptic - Egyptian Catholics who returned to communion with Rome in 1741. The Patriarch of Alexandria leads the 200,000 faithful of this ritual Church spread throughout Egypt and the Near East.  The liturgical languages are Coptic (Egyptian) and Arabic. Most Copts are not Catholics.

Ethiopian/Abyssinian - Ethiopian Coptic Christians who returned to Rome in 1846. The liturgical language is Geez. The 200,000 faithful are found in Ethiopia, Eritrea,  Somalia, and Jerusalem.

Eucharistic Adoration

3 Kings 7:48 "And Solomon made all the vessels for the house of the Lord: the altar of gold, and the table of gold, upon which the loaves of proposition should be set..."

2 Paralipomenon 2:4-2 "So do with me that I may build a house to the name of the Lord my God, to dedicate it to burn incense before him, and to perfume with aromatical spices, and for the continual setting forth of bread, and for the holocausts, morning and evening, and on the sabbaths, and on the new moons, and the solemnities of the Lord our God for ever, which are commanded for Israel."

Luke 22:19 "This is my body, which is given for you."

John 1:29  "Behold the Lamb of God. Behold him who taketh away the sin of the world."

John 6:32-36 ... "Then Jesus said to them: Amen, amen, I say to you; Moses gave you not bread from heaven, but my Father giveth you the true bread from heaven. For the bread of God is that which cometh down from heaven and giveth life to the world. They said therefore unto him: Lord, give us always this bread. And Jesus said to them: I am the bread of life. He that cometh to me shall not hunger: and he that believeth in me shall never thirst. But I said unto you that you also have seen me, and you believe not."

Apocalypse 2:17 "He that hath an ear, let him hear what the Spirit saith to the churches: To him that overcometh I will give the hidden manna and will give him a white counter: and in the counter, a new name written, which no man knoweth but he that receiveth it."


Reverence is shown to the Blessed Sacrament (the Eucharist) by our posture and gesture in the course of the Mass, and in countless other ways outside of Mass -- the genuflection toward the Tabernacle (in which the Sacrament is kept) upon entering a Church, the kneeling in the presence of the exposed Sacrament, women covering their heads when in the presence of the Sacrament, by crossing oneself when passing by a church to honor the Blessed Sacrament therein, etc. There are other ways of honoring Christ in the Eucharist, however, some formal, others not so formal. Below I will describe the following:

Click to jump to:
Visits to the Blessed Sacrament
Holy Hour
Forty Hours Devotion ("Quarant' Ore" or "Quarantore")
Perpetual Adoration
Benediction of the Blessed Sacrament


Visits to the Blessed Sacrament

The simplest, least formal, and most common way that Catholics honor Christ in the Eucharist outside of the Mass is by making simple visits to a Church to be near the Blessed Sacrament. They may go to pray, to sit quietly, to meditate, pray the Rosary, read Scripture, etc. As churches lock their doors now in response to the paganization of Western culture, it's become much more difficult to randomly visit a church and find it open to pay our respects, but one can possibly arrange with one's priest or with the parish office to be allowed inside during off-hours.

The Blessed Sacrament should be kept in the Tabernacle on the High Altar in the sanctuary, and with a sanctuary lamp ("ner tamid" to the ancient Israelites) burning nearby, but sometimes you might find the Tabernacle in a side chapel (often called a "Blessed Sacrament Chapel" or, if your parish offers Perpetual Adoration, a "Perpetual Adoration Chapel"). The tabernacle itself is the receptacle that holds the vessels that contain the Blessed Sacrament. It is lined inside with either gold or white silk, and is covered outside with a veil called a "canopeum."

Note: A partial indulgence is granted to the faithful, under the usual conditions, who visit the Most Blessed Sacrament to adore it; a plenary indulgence is granted, under the usual conditions, if the visit lasts for at least one half an hour. Note also that when women make a visit to the Blessed Sacrament (or any time they enter a church), they should cover their heads; men should uncover theirs.


Holy Hour

"Holy Hour" is a form of Eucharistic adoration made in response to a revelation by Christ to St. Margaret Mary Alacoque (1647-1690), as a part of our devotion to the Sacred Heart of Jesus.

Our Lord promised various things in return for receiving the Eucharist frequently (especially on the first Friday of each month for nine consecutive months, called "First Friday" Devotions), celebrating the Feast of the Sacred Heart, and spending one hour on Thursdays in Eucharistic adoration; this last is "Holy Hour."

Holy Hour at a particular church can be designated officially by one's priest, or it can be made privately if ones parish doesn't offer it as a public devotion. The focus of Holy Hour is Christ in the Garden of Gethsemani. In response to his question, "Couldst thou not watch one hour?" (Mark 14:37), we respond, "Yes, Lord, we are here with Thee."


40 Hours Devotion, or "Quarant'Ore"

The 40 Hours Devotion, introduced into Rome by St. Philip Neri in 1548, is the collective adoration of the exposed Eucharist for a period of 40 hours, in honor of the time Our Lord spent in the tomb (no single person is expected to spend 40 hours in adoration). While we say in the Creed that Christ was in the tomb for "3 days," those days are in the reckoning of the Old Testament religion, which counted any part of a day as "a day." In other words, Our Lord died at 3:00 on Friday (day one), descended into Hell (the afterworld) to save the righteous dead and laid in the tomb on Saturday (day two), and arose on Sunday morning (day three). In modern terms, we'd say He was in the sepulcher for "1 1/2 days or so" because some of those "days" are partial days, but those who practiced the Old Testament religion, and those who practice modern Judaism, would consider that time period "3 days." Counting the time by hours, however, we can see that from 3:00 PM Friday to 6:00 AM Sunday are 40 hours.

This devotion is often practiced during the Sacred Triduum (the three days before Easter which consist of Maundy Thursday, Good Friday, and Holy Saturday), but is also offered in times surrounding other great Feasts, or on regular schedules not related to the calendar at all.

When visiting the Blessed Sacrament as the 40 Hours Devotion goes on, we are to recite a sequence of an Our Father, a Hail Mary, and a Glory be 5 times -- the last cycle being for the intentions of the Holy Father. If one does this after having gone to Confession and received Communion, one receives a plenary indulgence (under the usual conditions).


Perpetual Adoration

Perpetual Adoration is, literally, perpetual Eucharistic Adoration, 24/7, all the way around the clock. Parishioners of a particular church volunteer to (or members of some religious communities are obliged to) take turns -- usually an hour -- to adore the Blessed Sacrament, working in "shifts." The adorer can pray, meditate, read Scripture, or simply sit in the presence of Christ.

Benediction of the Blessed Sacrament

MonstranceBenediction (Blessing) of the Blessed Sacrament can be a "stand-alone" service (most often done in the afternoon or evening), or as a part of other services, such as the Stations of the Cross, at major Feasts, during the Divine Office (especially after Vespers and Compline), etc.

The priest, wearing a cope, removes the Sacrament from the Tabernacle and places it in a monstrance (or "ostensorium") -- a usually elaborate sacred vessel used in the exposition of the Blessed Sacrament (see picture at right). The monstrance is placed on the Altar, which is adorned by (at least) six blessed candles. He will bless the Sacrament with incense, and O Salutaris Hostia is sung. Then all kneel in silent adoration. Other hymns, canticles, or litanties may be sung or said, or some of the Divine Office may be prayed, but always the Tantum Ergo is sung, usually as the priest once again incenses the Sacrament before the actual Benediction (Note: "O Salutaris" and "Tantum Ergo," two of the greatest Eucharistic hymns, were both written by St. Thomas Aquinas)

After the Tantum Ergo, the priest, wearing a humeral veil over his shoulders and hands, will raise the Monstrance over the congregation, making with it the Sign of the Cross to bless us. After this Benediction, the "Divine Praises" prayer is prayed, and the Sacrament is returned to the Tabernacle.

The Benediction of the Blessed Sacrament is a rite in which Jesus in the Sacrament of His love, is not only exposed to the adoration of the faithful, but in which He, present in that Sacrament, is implored to bless the faithful present before the Altar. It is not so much the Priest who blesses the people in this rite, as it is Jesus Christ Himself, in the Blessed Sacrament, who bestows His benediction upon them.

In this country, Benediction usually follows Vespers. After the final Antiphon of the Blessed Virgin is said, the Priest, vested in surplice, stole, and cope, goes up to the Altar, while the choir sings the O salutaris Hostia; and opening the Tabernacle, he makes a genuflection, and taking out a consecrated Host enclosed in a kind of locket. called a luna, places this in the centre of the Monstrance or Ostensorium- a stand of gold or silver, with rays like the sun. He then descends to the foot of the Altar, and puts incense in the censer; kneeling again, he receives the censer from the hand of the acolyte, and incenses the Adorable Host. When the choir sings the second line of Tantum ergo, all bow humbly down; then, during the Genitori, the Priest again incenses the Blessed Sacrament.

As soon as the choir has ended the hymn, the priest chants the Versicle; and after the Response he rises and chants the Prayer of the Blessed Sacrament. He then kneels again, and a veil is placed around his shoulders, after which he ascends again to the Altar, and , making a genuflection, takes the Monstrance, and , turning to the people, gives the Benediction in silence, making the sign of the Cross over the kneeling congregation.

Replacing the Host in the Tabernacle, he descends, and, preceded by his assistants, retires, while the choir chants the 116th Psalm, Laudate Dominum, omnes Gentes, or some other Psalm or Canticle permitted by Church authorities.

During this holy rite, the devout worshipper may either join in the chant of the choir, or pour out his soul in aspirations of love, adoration, gratitude, petition or contrition to the Sacred Heart of Jesus, thus humbled for our love.

Prayers for Benediction

O Salutaris Hostia
Note: The text of this hymn was composed by St. Thomas Aquinas and, along with Tantum Ergo, is strongly associated with Eucharistic Adoration, particularly, the Benediction of the Blessed Sacrament. There are variations on the melody.

O Salutaris Hostia
Quae coeli pandis ostium
Bella premunt hostilia
Da robur fer auxilium

Uni trinoque Domino
Sit sempi terna gloria
Qui vitam sine termino
Nobis donet in patria A-men.

Tantum Ergo

Latin Version   English version (Down in Adoration Falling):
Tantum ergo Sacramentum
Veneremur cernui
Et antiquum documentum
novo cedat ritui
Praestet fides supplementum
Sensum defectui
    Down in adoration falling,
Lo! the sacred Host we hail,
Lo! oe'r ancient forms departing
Newer rites of grace prevail;
Faith for all defects supplying,
Where the feeble senses fail.
Genitori, Genitoque
Laus et jubilatio
Salus, honor, virtus quoque
Sit et benedictio
Procedenti ab utroque
Compar sit laudatio. A-men
  To the everlasting Father,
And the Son Who reigns on high
With the Holy Spirit proceeding
Forth from each eternally,
Be salvation, honor blessing,
Might and endless majesty.

The Divine Praises / Laudes Divinae

English version:   Latin Version:
Blessed be God. Blessed be His Holy Name.   Benedictus Deus. Benedictum Nomen Sanctum eius.
Blessed be Jesus Christ, true God and true Man.   Benedictus Iesus Christus, verus Deus et verus homo.
Blessed be the Name of Jesus.   Benedictum Nomen Iesu.
Blessed be His Most Sacred Heart.   Benedictum Cor eius sacratissimum.
Blessed be His Most Precious Blood.   Benedictus Sanguis eius pretiosissimus.
Blessed be Jesus in the Most Holy Sacrament of the Altar.   Benedictus Iesus in sanctissimo altaris Sacramento.
Blessed be the Holy Spirit, the Paraclete.   Benedictus Sanctus Spiritus, Paraclitus.
Blessed be the great Mother of God, Mary most Holy.   Benedicta excelsa Mater Dei, Maria sanctissima.
Blessed be her Holy and Immaculate Conception.   Benedicta sancta eius et immaculata Conceptio.
Blessed be her Glorious Assumption.   Benedicta eius gloriosa Assumptio.
Blessed be the Name of Mary, Virgin and Mother.   Benedictum nomen Mariae, Virginis et Matris.
Blessed be St. Joseph, her most chaste spouse.   Benedictus sanctus Ioseph, eius castissimus Sponsus.
Blessed be God in His Angels and in His Saints.     Benedictus Deus in Angelis suis, et in Sanctis suis. Amen.

of the Blessed Sacrament

A "procession" is a religious "parade" during which the priest and people walk a route in honor of our Lord, Our Lady (or other Saints), or for the purpose of beseeching God for some specific purpose.

There are many types of regularly scheduled processions -- the procession with candles at Candlemas (2 February), the procession with palms on Palm Sunday (the Sunday before Easter), the "beating of the bounds" on Rogation Days, processions with statues of various Saints on their special feasts, etc. And there are processions of the Blessed Sacrament.

There are also a few true processions of the Blessed Sacrament that don't seem too "procession-like," such as the taking of the Sacrament to the Altar of Repose after the Mass on Maundy Thursday (the Thursday before Easter), and the return of the Sacrament on Good Friday during the "Mass of the Presanctified" that takes place that day. But there is also a "parade-like" Procession of the Blessed Sacrament, a procession that can take place at any time of the year, but which always takes place on the Feast of Corpus Christi (the Thursday after Trinity Sunday).

After the Mass on Corpus Christi, all kneel and sing O Salutaris Hostia. The Host is incensed, and carried under an ombrellino (an umbrella-like canopy) to the baldacchino, a rectangular tent-like canopy that is rather like a Jewish chuppah.

Then the procession forms, led by the Crucifer (the acolyte who carries the processional Cross), who is flanked by acolytes carring candles. Then follow members of religious associations and orders, children strewing rose petals in the path of the Blessed Sacrament (they are customarily dressed in their First Communion clothes), clergy, and then two thurifers who incense the path. Then comes the Blessed Sacrament, carried at eye-level by a priest (with his hands veiled) in a monstrance, under the baldacchino, all flanked by torch bearers. The people walk behind.

Usually four stops are made, and at each come Gospel readings, prayer, the singing of Tantum Ergo, and a Benediction of the Blessed Sacrament. After the last stop, all process back to the church and sing the Divine Praises.

Note: Those who own homes along the procession route decorate them for the occasion. While this isn't common in America and other nominally Protestant nations, you will still see it in southern European and other Latin countries. Also, if you ever see a Procession of the Blessed Sacrament pass by and you're unable to join in, you are to kneel on both knees in adoration, covering your head if you're a woman, and uncovering it if you're a man -- as always when in His Sacramental Presence -- until the procession passes.