You might be interested in Fr. Anthony Ruff’s defense of the term performance in the context of liturgy, which I find persuasive. Too often people use the term performance, always in snarling tones, to music they do not like – and the forbidding of anything at all resembling a performance has been used to rule out anything artistically accomplished from taking place at Mass. See page 383 of Sacred Music and Liturgical Reform (1987).
Jeffrey,
I have always been taught that sacred and liturgical music in the context of the Mass is prayer. Thus, as a very humble chorister, a main component of my task in singing is to support the parish congregation's participation in the musical forms of prayer, in both hymnody and chant. I think you have captured the sense of this in your post, and I know our Director of Liturgy and Music agrees with your usage of "performance." This very much requires that we see our singing as very distinctly different than a form of entertainment performed for the congregation.
Pax et bonum,
Keith Töpfer
music express that which cannot be put into words and cannot remain silent