Q. 1. What is the "Introit?"

A. 1. The Introit (from Latin: introitus, "entrance") is part of the opening of the Holy Mass in the Catholic Church. In its most complete version, it consists of an antiphon, psalm verse and Gloria Patri that is spoken or sung at the beginning of the celebration. It is part of the Proper of the liturgy; that is, the part that changes over the liturgical year.

The Introit of the Mass, the fragment of a psalm with its antiphon, is sung while the priest enters the church and approaches the altar. In all Western rites the Mass began with such a processional psalm since the earliest times of which we have any record. As it was sung by the choir it is not, of course, to be found in sacramentaries; but introits are contained in the first antiphonaries known (the Gregorian Antiphonary at Montpellier, the St. Gall manuscript, that represent a seventh-century tradition.

For more detailed information, please visit the following sources:

• Wikipedia Encyclopedia
https://en.wikipedia.org/wiki/Introit

• Webster Dictionary
https://www.merriam-webster.com/dictionary/introit

• Catholic Encyclopedia
http://www.newadvent.org/cathen/08081a.htm