Another use of the term “ordinary” in Catholic liturgical parlance is to identify prayers that are always included in the liturgy, as opposed to the “propers”, which are prayers specific to a particular day. With very few exceptions, all these prayers have prescribed texts, translated from the official Latin text.
In the current Roman missal, most of the ordinary prayers have several options, and the priest who is celebrating mass may select which option will be used.
Were you aware that there were some prayers that were always used, and some that were specific to the day? What do you think about that?
The Gloria begins with the words that the angels sang to the shepherds, according to Luke 2:13-14:
And suddenly there was a multitude of the heavenly host with the angel, praising God and saying:
“Glory to God in the highest
and on earth peace to those on whom his favor rests.”
(The exact wording of that second line depends both on which Greek manuscript is being followed, and how it is translated. The above is taken from the NABre, which explains in a footnote that it follows the Western and Alexandrian manuscripts rather than the Byzantine, which read “good will towards people.”)
And so it is a particularly Christmasy text. This is why we abstain from singing or saying the Gloria during Advent: so we can sing it at Christmas mass, as if for the first time, with the multitude of angels. (Did you notice we were omitting it during Advent?)
Here’s a setting of the Gloria from Marty Haugen’s Mass of Creation, which is one of the most commonly known Mass settings among American Catholics: