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What's a TLM, anyway? A Latin liturgy lexicon

Rome has been full of reports in recent weeks predicting that Pope Francis will soon modify the norms of Summorum pontificum, a 2007 document which granted wide latitude for priests to celebrate the “Extraordinary Form” of the liturgy.

It remains to be seen when the pope will approve any changes to the current norms, or what the potential changes could be. 

In the meantime, at least some Catholics find themselves a bit confused by terms like the “Ordinary Form” and the “Traditional Latin Mass,” and even more confused trying to keep straight the FSSP, the SSPX, and the other acronyms and jargon that tend to pop up in this conversation.

To help you navigate the coverage, and to make sure you know your ars from your introit, The Pillar presents a Latin Liturgy Lexicon.

A priest offers the Extraordinary Form of the Mass. Credit: Priestly Fraternity of Saint Peter, available from .

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The Roman Missal

The Roman Missal is the Church’s book of prayers and instructions for celebrating Mass in the Latin Catholic Church. The Eastern Catholic Churches in full communion with Rome each have their own liturgical rites. 

New editions of the Missal are periodically released. The major reform of the Roman Missal following Vatican Council II was approved by Pope St. Paul VI in 1969 and published in 1970. It has been updated several times since then, most recently in 2008.

Extraordinary Form / Ordinary form

In 2007, Pope Benedict XVI introduced the terms Ordinary Form and Extraordinary Form to describe the two most predominant forms of the Roman rite, the Mass ordinarily celebrated by the Latin Catholic Church. 

The Ordinary Form of the Mass is contained in the current version of the Roman Missal. It is the form of the Mass introduced when the liturgy was reformed in the years following Vatican Council II. If you go to Mass at your parish, and you’re not sure what “form” of the Mass you attend, you probably go to the Ordinary Form. 

The Ordinary Form usually looks like this:

Cardinal Vincent Nichols celebrates the Ordinary Form of the Mass in Westminster Cathedral. Credit: Mazur/

The Extraordinary Form of the Mass is celebrated according to the 1962 Roman Missal (and sometimes from missals issued earlier than that), which was in place before the reforms that followed the Second Vatican Council and was promulgated by Pope St. John XXIII. 

Since 2007, priests have been permitted to offer the Mass according to this form broadly — in private whenever they wish, and for a public group when a community of Catholics request it. Before 2007, priests had generally required permission from the local bishop to offer the Extraordinary Form of the Mass.

Since 2007, the Extraordinary Form has grown in popularity, both in parishes or chapels administered by priests who celebrate it all or most of the time, and as an option in ordinary parishes. 

The Extraordinary Form usually looks like this:

The Extraordinary Form of the Mass offered in Stasbourg Cathedral. Credit: Christophe117/wikimedia CC BY SA 4.0

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‘Novus ordo’

Another term for the Ordinary Form of the Mass.

Novus ordo is shorthand for Novus Ordo Missae, or “the new order of the Mass.”

Traditional Latin Mass/’TLM’/Tridentine Mass/ usus antiquior

Other terms for the Extraordinary Form of the Mass.

Some Catholics actually prefer the liturgy in versions of the Missal prior to the 1962 edition, which incorporated a number of changes to the liturgical calendar and to different liturgical celebrations, especially during the Easter Triduum. 

Summorum Pontificum

A 2007 motu proprio issued by Pope Benedict XVI, permitting Latin Catholic priests to celebrate the Extraordinary Form of the Mass privately, and in public “in parishes where a group of the faithful attached to the previous liturgical tradition stably exists,” doing so “under the governance of the bishop.”

Last year, the Congregation for the Doctrine of the Faith issued a survey to bishops that aimed to assess how the motu proprio is working at the diocesan and parish levels. It is widely reported that the results of this survey prompted Vatican discussion about possible changes to the motu proprio’s provisions.


High Mass, Low Mass, and Solemn Mass

The Extraordinary Form of the Mass has three primary options for offering the Mass: usually called “high,” “low,” and “solemn” Mass. 

At a High Mass, the priest celebrating chants or sings most of the liturgical prayers, makes more frequent use of incense during the liturgy, and has a large number of altar servers. Some of the responses of the congregation are sung by a choir called a schola.

A High Mass is also called a “Missa Cantata,” or “sung Mass.”

A Solemn Mass is like a High Mass, but the priest is assisted by a deacon and a subdeacon (the terms are used in this context for liturgical roles, which are in fact often filled by priests acting liturgically in the roles of deacon and subdeacon.)

When a bishop celebrates a Solemn Mass, it’s called a Solemn Pontifical High Mass and it has some extra ceremonies.

A Solemn Pontifical High Mass looks like this:

Credit: J.A.Bergeijk/wikimedia. CC BY SA 3.0

Watch a Solemn Pontifical High Mass, with play-by-play, here:

At a Low Mass, the priest says, rather than sings or chants, the liturgical prayers. There is no schola, and the liturgy is much quieter — and briefer.

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Ad orientem

This term means “to the East.”

It usually refers to Mass offered by a priest who is mostly facing the altar, but not facing the people, as he offers some of the Mass’ liturgical prayers. 

All Masses in the Extraordinary Form are offered ad orientem, and — in some places -- the practice is growing in popularity in the Ordinary Form as well.

Some liturgists say ad orientem is the ritual book’s expected way to celebrate the Ordinary Form, even though it is not common in most churches.

Read more about the theology of offering Mass ad orientem here.

Mass offered ad orientem looks like this:

Bishop James Conley offers the Ordinary Form of the Mass ad orientem. Credit: Southern Nebraska Register.

The vernacular  

The language ordinarily spoken by the people of a region or nation. 

In the modern era, Mass began to be celebrated in the vernacular after the Second Vatican Council. It was before then celebrated mostly in Latin, with some exceptions, and continues to be offered in Latin in the Extraordinary Form.

The official text of the Ordinary Form is also written in Latin, and the Ordinary Form can be, and sometimes is, offered in Latin too. People usually refer to such a Mass as Latin Novus ordo

A Latin Novus ordo sounds and looks like this:

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The Society of St. Pius X (SSPX) is a priestly fraternity which opposes the post-Vatican II liturgical reforms. It is in “imperfect communion” or “institutional irregularity” with the Church, and it has a storied history.

The society was founded in 1970 by Archbishop Marcel Lefebvre, who was excommunicated in 1988 after consecrating four bishops without permission from Pope John Paul II. 

Pope Benedict XVI lifted the excommunication of the bishops in 2009. At the same time, he clarified that the SSPX has no canonical status, and said its priests could not exercise legitimate ministry.

The society has had discussions with Vatican officials over the years about re-entering full communion with the Church. 

The Church has said that while some communion exists between the Church and the SSPX, it is “imperfect communion” and further reconciliation, or “institutional regularization” is still needed.

Pope Francis has continued Benedict’s dialogue with the SSPX, aiming towards reconciliation. He extended priests of the society the faculty to hear confessions during the Year of Mercy in 2015, and extended that faculty indefinitely the following year.

In 2017, Pope Francis also said that under very limited circumstances, diocesan bishops could give priests of the SSPX the faculty to validly witness marriages.

Those sacramental concessions have focused on the spiritual good of Catholics who attend chapels administered by the SSPX. Pope Francis has emphasized that he does not want Catholics who attend those chapels to be without the possibility of confession, especially, or a way to marry validly. 

But many bishops have also discouraged Catholics from attending SSPX chapels because of their irregular canonical status, and one bishop has even declared that Catholics who join SSPX chapels can be subject to excommunication.  



The Priestly Fraternity of St. Peter (FSSP) is a society of priests in full communion with the Church.

Its founders were initially part of the Society of St. Pius X (SSPX), but broke away in 1988 when the head of the SSPX consecrated four bishops illicitly. 

The FSSP’s founders, with support from Pope St. John Paul II, wanted to found an association of priests celebrating the Extraordinary Form of the Mass while remaining in the full communion of the Church. 

Today, with the permission of local bishops, the FSSP administers chapels and parishes in dioceses around the world, including many in the United States. It operates two seminaries, one in Germany and the other, Our Lady of Guadalupe, is located in Nebraska.


The Institute of Christ the King Sovereign Priest (ICKSP) is another society of priests who offer the Extraordinary Form of the Mass as a central aspect of their identity. It is in the full communion of the Catholic Church.

In the United States, the ICKSP has ministries in 10 states, and its national headquarters is in Chicago.

Among other things, the ICKSP has developed a reputation for some pretty bad-ass processions:

A 2019 procession of the ICKSP. Credit: Detroit Catholic.

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Ecclesia Dei

The pontifical commission Ecclesia Dei was established by Pope St. John Paul II in 1988, in response to the schism caused by the SSPX bishops. In addition to working for the reform and return of the SSPX clergy, the commission was also charged with the care of Catholics who had a deep attachment and devotion to the “old” form of the Mass.

Over the years, it worked to reconcile numerous breakaway traditionalist communities to full communion with the Church, even with somewhat limited success.

In 2019, Pope Francis merged the work of Ecclesia Dei into the Congregation for the Doctrine of the Faith, noting that much of the commission’s work was doctrinal in nature.


A position held by a very small number of Catholics, which says that there is not presently a validly elected pope. Sedevacantists — who disagree among themselves on who the last valid pope actually was — can usually be found in very small breakaway traditionalist communities.


A position held by a very small number of Catholics, which says that Benedict XVI remains the validly elected pope. Benevacantists, who hold that Benedict’s resignation of the papacy was not a valid act, can usually be found online.

Pope Michael

A Kansas man, David Bawden, who holds that he was validly elected pope in 1990, and that between the death of Pope Pius XII in 1958 and his election in 1990, there was no valid pope. Bawden has been validly ordained a priest and consecrated a bishop by other renegade breakaway figures. 

While he has only a few dozen followers at most, Pope Michael has been a pop culture icon among some young Catholics, and has been the subject of numerous articles and a documentary.

Pope Michael in 1990. Credit: PapaVaticana/wikimedia. CC BY SA 4.0

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