The trend has been from "celebrating Mass" to "celebrating the Eucharist" to now "celebrating Eucharist". The idea of removing the term Mass was for a number of reasons:
- the perception that the word Mass came from the word "Missa" whihc referrred to the dismissal at the end of Mass" and not really what happens in the Mass
- a move away from Catholic terms to a more protestant friendly term.
Mind you this seems to be a term used only in the English speaking world, other places eg Italy only use Messa or Sancta Messa (or Holy Mass)
I cannot understand why "the" has now beeen dropped. I suspect it might have been to give a bigger emphasis on the community celebrating (like we have "lunch" not "the lunch"). I think this is an attempt to make the meal aspect of the whole liturgy a lot stronger. Not a good trend.
I think this is traditionally called the introit or "entrance". Where did gathering come into it? I thought that the gathering happens before this when the people gather in the church prior to the commencement of the liturgy. The GIRM calls it the entrance and the the music accompanying it the "entrance chant". Again the use of the word "song" creeps into local usage. This has been condemned by the Congregation for Divine Worship, as this does not refer to a liturgical act, and the word song does not appear in GIRM.
Presentation of the Gifts
This is another way of saying offertory. However, the intent is that it emphasises the people presenting the gifts whihc has a sense of "horizontality" in it. Offertory is presumably avoided as it is a priest action and accentuates the "verticality" of the liturgy.
This is the real odd one. The term presiding has been used since the early church. However, it appears to be used now to emphasise that it is the congregation does the liturgy and the priest merely presides over or chairs the proceedings. The problem stems from the GIRM n30-33, whihc talks about the priest presiding over the assembly "in the name of Christ" and "as the one who presides, prays in the name of the Church and the assembled community". This of course points strongly to an orientation that he faces towards the people; quite different to the extraordinary form where the priest prays in the "name of the people" and is not presiding over anything that the community actually does.
Thesea re all terms which I feel uncomfortable about. However, the seeds of them are all there in the GIRM and have been used effectively by the people who would push us towards protestantism, where a priesthood is not present.