I was reading the Summa theologiae of Saint Thomas Aquinas today on the liturgy of the Holy Eucharist and I came across this interesting etymology of the term missa from which we derive the English word “Mass.” Many people say that “Ite missa est,” refers to a dismissal of the people, i.e. “The assembly is dismissed.” However, Thomas refers it to the priest “sending” the prayer or the victim Christ to God, as in: “The prayer is sent.”

And from this the mass derives its name [missa; because the priest sends [mittit] his prayers up to God through the angel, as the people do through the priest. or else because Christ is the victim sent [missa] to us: accordingly the deacon on festival days “dismisses” the people at the end of the mass, by saying: “Ite, missa est,” that is, the victim has been sent [missa est] to God through the angel, so that it may be accepted by God. {STh III, q. 83, a. 4}