introit

Etymology

PIE word *h₁én from a 14th- or 15th-century missal. The fourth passage, up to the first word of its third line, is the introit (sense 1), and reads “Laetabitur justus in Domino, et sperabit in eo: et laudabuntur omnes recti corde” (“The just shall rejoice in the Lord, and shall hope in him: and all the upright in heart shall be praised”).]] From Late Middle English introite (“act of entering in or into, entrance; place of entrance”), borrowed from Old French introït, introïte (“introit”) (modern French introït), or from its etymon Latin introitus (“act of entering in or into, entrance; passage; place of entrance; (figuratively) beginning, introduction, prelude”), from introeō (“to enter, go in”) + -tus (suffix forming action nouns from verbs). Introeō is derived from intrō (“to enter, go into”) (ultimately from Proto-Indo-European *h₁én (“in”)) + eō (“to go”) (ultimately from Proto-Indo-European *h₁ey- (“to go”)).

noun

1. (Roman Catholicism, music) A prayer, typically part of a psalm or other portion of the Bible, read or sung at the start of Mass while or immediately after the priest ascends to the altar.
   The Glossary of Terms used by ecclesiastics in the middle ages, who describe a day by the “introit,” or commencement of the service appointed by the church to be performed thereon, and an explanation of the Canonical Hours, Watches, &c. will frequently be found useful.] [1833, [Nicholas] Harris Nicolas, “Preface”, in Dionysius Lardner, editor, The Chronology of History.[…] (The Cabinet Cyclopædia; XLIV), London: […] Longman, Rees, Orme, Brown, Green, & Longman,[…]; and John Taylor,[…], →OCLC, page xvii
   Adorate Dominum. The introit* and name of the third Sunday after the Epiphany. [Footnote *: Introit.—The first two or more words that form the commencement of a mass, which, from being appropriated to a certain Sunday, or other festival, give the name of such commencement or "introit" to these days.] 1833, [Nicholas] Harris Nicolas, “A Glossary of Dates;[…]”, in Dionysius Lardner, editor, The Chronology of History.[…] (The Cabinet Cyclopædia; XLIV), London: […] Longman, Rees, Orme, Brown, Green, & Longman,[…]; and John Taylor,[…], →OCLC, page 110, column 1
   At some time during these sacerdotal preces the choir will usually have started the sung introit, the exact time for beginning the item dependent on a number of features such as the distance from sacristy to altar. 1982, Andrew Hughes, “Mass”, in Medieval Manuscripts for Mass and Office: A Guide to Their Organization and Terminology, Toronto, Ont., Buffalo, N.Y.: University of Toronto Press, published 2004, page 84
   The earliest unequivocal reference to the Roman introit is from the turn-of-the-eighth-century Ordo romanus I, where the chant is described in its fully developed early medieval form. Consisting of an antiphon and psalm, it is sung during the entrance of the pope at the beginning of Mass. 2000, James [W.] McKinnon, “The Introit”, in The Advent Project: The Later-seventh-century Creation of the Roman Mass Proper, Berkeley, Los Angeles, Calif., London: University of California Press, page 195
2. (Christianity, chiefly Protestantism, music) Any piece of vocal music, especially a setting of an anthem or a psalm, sung at the opening of a church service.
3. (obsolete) The action of entering or going in; an entrance.
4. (obsolete, figurative) An introduction.