Those who spend time in liturgical discussions are guaranteed to encounter at some point the following objection: “You shouldn’t be speaking of the ‘Novus Ordo’ or the ‘Novus Ordo Mass.’ This isn’t what it’s called. That’s a traditionalist label — a way of attacking the reformed missal of Pope St. Paul VI,” etc.New Liturgical Movement: Are We Justified in Calling Paul VI’s Creation the “Novus Ordo [Missae]”?
Those who spend time in liturgical discussions are guaranteed to encounter at some point the following objection: “You shouldn’t be speaking of the ‘Novus Ordo’ or the ‘Novus Ordo Mass.’ This isn’t what it’s called. That’s a traditionalist label — a way of attacking the reformed missal of Pope St. Paul VI,” etc.
This matter deserves a closer look.
While “Novus Ordo [Missae]” is not a typical way in which the Vatican itself, post-1969, has preferred to denominate the Order of Mass created by the Consilium and promulgated by Paul VI on April 3, 1969, it is nevertheless a phrase found in a couple of official documents and does not seem to have ruffled feathers until later on.
The first thing to establish is that Paul VI constantly attached the word “new” to his ongoing liturgical reforms of the 1960s. For example, in his general audience of March 7, 1965, he spoke of a “new order [of worship],” a “new scheme of things,” “new liturgical books,” “new form,” “new liturgy,” “new habit,” and “liturgical innovation” — and all this, about changes far less drastic than those he would promulgate four years later. A fortiori, the application of novus to the missal of 1969 is entirely justified on the basis of its own promulgator’s habits of speech.
Let us not forget that many things people today would assume must have entered with the Novus Ordo in 1969 were already around prior to it, as the traditional liturgy was progressively dismantled in the 1950s and 1960s: turning the priest toward the people, which first happened with Pius XII’s lamentable Palm Sunday service; having the people say the Lord’s Prayer at the liturgy together with the priest, something never done in the Roman tradition prior to Pius XII’s new Good Friday; praying the Mass in the vernacular, which came in here and there experimentally; dropping the prayers at the foot of the altar and the last Gospel, a cropping that happened in 1965; bringing in new ad experimentum lectionaries; the admission of multiple Eucharistic Prayers; the discarding of some liturgical vestments; and so forth.
Coming nearer to our topic: in the general audience of November 19, 1969, which attempted to explain why a new missal was to be imposed, Paul VI — this time with much greater justice — referred to “a new rite of Mass” (four times), “a new spirit,” “new directions,” “new rules,” “innovation.” In the general audience one week later, he mentioned “the liturgical innovation of the new rite of the Mass” and mentioned the “new rite” seven times; he used words like “new,” “newness,” “renewal,” “innovation,” “novelty,” a total of 18 times. I comment in detail on these two general audiences in chapter 4 of my new book from TAN, The Once and Future Roman Rite: Returning to the Latin Liturgical Tradition after Seventy Years of Exile. 
Interestingly, Cardinal Alfredo Ottaviani, one of the highest ranking Vatican prelates (in spite of the enormous hatred directed at him by the anti-Roman faction at the Council) and for a long time the head of the Holy Office, used the phrase “Novus Ordo Missae” 18 times in the famous “Ottaviani Intervention” of September 25, 1969 — more properly entitled Short Critical Study of the New Order of Mass — co-signed with Cardinal Antonio Bacci and submitted to Paul VI.  He employs the expression as if it is quite obvious, familiar, and unobjectionable, and to my knowledge no one at the time disputed the appropriateness of it, even though much else in the critical study was the subject of hot debate.
To my knowledge, the first time the expression “Novus Ordo Missae” shows up in a papal magisterial document is in an address delivered by Paul VI (text here) at a consistory for the appointment of twenty cardinals on May 24, 1976. In this address he uses the expression novus Ordo [Missae]: “usus novi Ordinis Missae” and “novus Ordo promulgatus est” (“the use of the new Order of Mass”; “the new Order has been promulgated”). 
In April of 2010, the Office for the Liturgical Celebrations of the Supreme Pontiff placed a short document on the Vatican website entitled “The Priest in the Concluding Rites of the Mass.” Surprisingly, although the text is redolent of Benedict XVI and the reign of his MC Guido Marini, and although it refers plentifully to “ordinary” and “extraordinary” forms, it still remains on the Vatican website (here). This document refers to the “Novus Ordo” (tout court) and the “Vetus” [Ordo], albeit using scare quotes for the latter term.
All of the foregoing was known to me prior to discovering an article at Pray Tell by Max Johnson dated January 14, 2010: “From Where Comes ‘Novus Ordo’?” (Would that Pray Tell had opted for the more eloquent title “Whence Cometh ‘Novus Ordo’?,” but the spirit of Comme le Prévoit has long prevailed in those quarters.) As one would expect, the article complains that the phrase has become weaponized by traditionalists into a “title” for the Mass instead of being a simple passing description, like saying “new hymnal” or “shiny new book,” that has no substantive (theological) meaning. This view would seem to be difficult to sustain in light of Paul VI’s veritable paean to innovation in the 1969 audiences mentioned above. The changes made to the Mass are not merely incidental or superficial, like a new typeface or a new binding for a missal, but cut into the bone and marrow of the rite.
The conclusion I reach is, understandably, quite different from Pray Tell’s. I think it is fair to call the Consilium’s fabrication “novus,” which means both novel and strange. Whatever is it, it is most definitely not the Roman rite, as I demonstrate on multiple grounds in The Once and Future Roman Rite. The relentless traditionalist critique has indeed made of “Novus Ordo [Missae]” a pejorative term — and that is no worse than it deserves.
 That chapter itself is a revised and expanded version of a lecture whose text may be found here.
 A note about terminology. Nowadays the phrase “Novus Ordo” has been extended to mean virtually the same thing as “the reformed liturgical rites.” Thus, one will hear people speak of the “Novus Ordo baptism,” “Novus Ordo breviary,” and the like. Although we readily understand what is meant, it would be more accurate to say the “new rite of baptism,” the “new liturgy of the hours,” and so forth, since “Novus Ordo” is just an abbreviated form of “Novus Ordo Missae”: it is specifically about the order of Mass followed in the offering of the Eucharist. However, one may justifiably refer to the “Novus Ordo lectionary” and “Novus Ordo calendar” because of how closely associated they are with the liturgical books for the Mass.