To that end, Gregory compiled some brief descriptions of some of the technical terms used for parts of the Divine Office. Where available, he has provided a link to the relevant article within the Catholic Encyclopedia, where more detailed information may be found.
Compendium of the Reforms of the Roman Breviary, 1568-1961
by Gregory DiPippo
for publication on the New Liturgical Movement
Supplement: Glossary of Terms Related to the Divine Office
Antiphon – A sentence or phrase set to a melody, sung before and after the Psalms and Canticles of the office. See: http://www.newadvent.org/cathen/01575b.htm
Antiphon of the Virgin (final antiphon) – One of the four great antiphons in honor of the Virgin, varying according to the season; accompanied by a versicle, respond and prayer. Formerly said at the end of every hour in choir, now traditionally only at Compline. See:
Athanasian Creed – A Creed traditionally ascribed to St. Athanasius, containing a lengthy explanation of the dogma of the Trinity, written for liturgical use, and said at Prime in the same manner as the psalms. See: http://www.newadvent.org/cathen/02033b.htm
Benedicite – The Old Testament canticle of the Three Children, Daniel 3, 57-88 and 56, sung every Sunday and feast day at Lauds, before the reform of 1911.
Benedictus – The New Testament canticle of Zacharias, St. Luke 1, 68-79, sung every day as the most important feature of Lauds. See: http://www.newadvent.org/cathen/02473a.htm
Canticle – A passage of the Old or New Testament, arranged and sung in the same manner as the psalms. The Old Testament canticles supply the fourth psalm of Lauds every day. See: http://www.newadvent.org/cathen/03301a.htm
Chapter – A brief passage of Scripture, read without a title at every hour except for Matins, and answered with the words “Deo gratias.” See: http://www.newadvent.org/cathen/12424a.htm
Chapter Office – The second part of Prime, consisting of the Martyrology, a series of versicles and prayers which do not vary from day to day, and a short reading. See: http://www.newadvent.org/cathen/12424a.htm
Commemoration – The recitation of an antiphon, versicle, respond, and prayer of an office which cannot be said in full because of the occurrence of another office on the same day. See: http://www.newadvent.org/cathen/04155a.htm
Doubling of antiphons – In the Roman use of the Office, the singing of an antiphon in full before and after the psalm or canticle to which it belongs. cf. semidoubling.
Duplex (double) – In the Roman use of the Office, the highest grade of feast, on which all the antiphons of Matins, Lauds and both Vespers are doubled (q.v.); such an office regularly has three nocturns at Matins. In later editions of the Tridentine Breviary, subdivided into four classes: duplex I classis, duplex II classis, duplex majus, duplex minus – first class, second class, major and minor. A duplex is presumed to be ‘minor’ unless otherwise noted.
Feria – Any day of the week other than Sunday. See: http://www.newadvent.org/cathen/06043a.htm
Gradual Psalms – The Psalms from 119 to 133, said with certain versicles and prayers for the benefactors of the Church, both local and universal. See: http://www.newadvent.org/cathen/06718a.htm
Homily – In the context of the Breviary, a reading from the Church Fathers, commenting on the Sunday or feast day’s Gospel. In pre- and post-Tridentine breviaries, generally confined to the third nocturn. Many ferias, such as those of Lent, also have a homily instead of Scriptural readings in their sole nocturn. Cf. Sermon. See: http://www.newadvent.org/cathen/07448a.htm
Invitatory – A brief refrain, often including the words “venite, adoremus - come, let us worship”, repeated after the verses of Psalm 94.
Little Office of the Virgin Mary – A votive office in honor of the Virgin, much shorter and much more repetitive than the principal office. Originally appointed for daily recitation in addition to the main office, but in practice frequently omitted. See: http://www.newadvent.org/cathen/09294a.htm
Magnificat – The New Testament canticle of the Virgin Mary, St. Luke 1, 46-55, sung every day as the most important feature of Vespers. See: http://www.newadvent.org/cathen/09534a.htm
Martyrology – Originally a catalog of martyrs, later expanded to include all kinds of Saints and feasts. Read at Prime at the beginning of the Chapter Office; the reading is always that of the following day’s entry. See: http://www.newadvent.org/cathen/09741a.htm
Nocturn – The second part of Matins, after the Invitatory and Hymn. Each nocturn consists of a certain number of psalms with their antiphons, a versicle and respond after the last antiphon, the Lord’s Prayer (said silently), a short prayer called an absolution, and three readings from the Bible, the Church Fathers or the lives of the Saints, preceded by a blessing of the reader, and followed by a prolix responsory. The Te Deum is sung after the last reading on most Sundays and all feasts. See: http://www.newadvent.org/cathen/11087b.htm
Nunc dimittis – The New Testament canticle of Simeon, St. Luke 2, 29-32, sung every day as the most important feature of Compline. See: http://www.newadvent.org/cathen/11159a.htm
Octave – The prolongation of a major feast through an eight day period. See: http://www.newadvent.org/cathen/11204a.htm
Office of the Dead – A votive office prayed for the repose of the dead, much shorter and much more repetitive than the principal office. Originally appointed for daily recitation in addition to the main office, but in practice frequently omitted. See: http://www.newadvent.org/cathen/11220a.htm
Penitential Psalms – Psalms 6, 31, 37, 50, 101, 129 and 142. Said with a single antiphon, as a act of penance.
Preces – A series of versicles and responsories, said before the Prayer of the hours except for Matins. At Prime and Compline, they are omitted on the higher grades of feasts and their octaves. At the other hours, they are said only on ferial days of a penitential character.
Responsory, ‘prolix’ or major – A more or less complicated melodic piece sung after each lesson at Matins. Divided into two parts, labeled R. (for responsory) and V. (for verse.) The second part of the R. is repeated after the Verse. See: http://www.newadvent.org/cathen/12787a.htm
Responsory, ‘short’ or minor – A melodic piece of simple melody, sung after the Chapter of Terce, Sext and None, after the hymn of Compline. Divided into two parts, labeled R. br. (for short responsory) and V. (for verse.) The order of the repetitions is similar to that of the prolix responsories. See: http://www.newadvent.org/cathen/12787a.htm
Semidoubling of antiphons – In the Roman use of the Office, the singing of just the beginning of an antiphon before and after the psalm or canticle to which it belongs; the antiphon is then sung in full only after the psalm or canticle. Formerly the norm in the Western form of the Divine Office. cf. doubling.
Semiduplex (semidouble) – In the Roman use of the Office, the second grade of feast, on which none of the antiphons are doubled (q.v.); such an office regularly has three nocturns at Matins.
Sermon – In the context of the Breviary, a reading from the Church Fathers, relating to the feast day or Sunday on which it is read. In pre-Tridentine breviaries, often read in the first and second nocturn; in the Tridentine Breviary, limited to the second only. Cf. Homily.
Simplex (simple) – In the Roman use of the Office, the third and lowest grade of feast, on which none of the antiphons are doubled (q.v.); such an office has only one nocturn at Matins.
Suffrage – The recitation of an antiphon, versicle, respond, and prayer, in honor of a particular Saint or mystery, as a votive commemoration. They may vary according to the season, but are not connected to the liturgical calendar. See: http://www.newadvent.org/cathen/04155a.htm
Te Deum – The hymn of Thanksgiving par excellence of the Roman Rite. Sung on Sundays and feasts after the last lesson of Matins. Traditionally ascribed to Saints Ambrose and Augustine, written on the occasion of the latter’s baptism, and called for this reason “the hymn of Saints Ambrose and Augustine.” See: http://www.newadvent.org/cathen/14468c.htm
Versicle – A sentence or phrase sung in choir by the leaders of the chant in a particular melody, usually quite simple. The answer is called the Respond; it is sung by every one in the choir in exactly the same melody. Abbreviated in liturgical books with V. and R. E.g. on Christmas, V. God hath made known, alleluja. R. His salvation, alleluja.
Vigil – A day of preparation before a major feast; in the Missal, a Mass after None on such a day, of penitential character; in the Breviary before Trent , sometimes used to mean the first vespers of a feast.