(Note: Most of these terms have complex lineages, so we have oriented our brief definitions for usefulness with the Ege leaves. For more information, we recommend the Catholic Encyclopedia at http://www.newadvent.org/.)
Antiphon, Antiphonal: A brief transitional sentence taken from the Psalms or elsewhere in the Bible, and sung or spoken in response to a Psalm during a religious service such as the Mass. It usually involves alternation between the presider or choir and the congregation. The word also refers to a kind of book (variously called an antiphonal, an antiphonary, or an antiphoner) which contain these texts and their music. One Ege leaf (number 27) comes from an antiphonal manuscript, but many more contain individual antiphons; the latter are often marked with a rubricated (red) "A."
Apocrypha: Books outside a traditional scriptural canon. The word can refer to the books that were included in the Catholic scriptures but not in the Hebrew scriptures (such as the fourth book of Esdras), for example, or to those found in the Hebrew and resultantly Catholic "Old Testament" but not in the Protestant Bible. Among Ege's Bible leaves are many from apocryphal books such as Tobit, Judith, and Wisdom.
Bible: A large codex book containing the Christian scriptures. It is always divided into the Old and New Testaments with the division being the life of Christ; the latter is narrated in the four Gospels (Matthew, Mark, Luke, and John) which are held in highest reverence.
Book of Hours: A collection of prayers which were, at different times, obligatory or optional, and marked the canonical hours of the day such as Lauds or Matins. Books of Hours were a true bookmaking phenomenon of the later Middle Ages (from the 12th through the 15th centuries), and many thousands of them have survived into the 21st century. Ege's leaves give a good sense of the wide variation in contents and decoration of these popular and beautiful prayerbooks; 12 of the 50 leaves in the Ege portfolios (numbers 24, 28, 29, 30, 31, 36, 43, 45, 46, 47, 48, and 50) are from Books of Hours.
Breviary: A book containing texts and instructions for the celebration of Mass and other canonical offices. Breviaries are usually structured according to the season (spring, summer, fall, and winter), within each of which are contained a Psalter, the Proprium de Tempore (the special office of the season); the Proprium Sanctorum (the special offices of saints); the Commune Sanctorum (the general offices for saints); and various extra services. In the Ege portfolios Leaves 16, 18, and 23 are from breviaries.
Epistolary: A book containing only lessons from the epistles (i.e., letters), that is the books in the New Testament. In the Ege portfolios Leaf 37 is from an epistolary.
Gradual: A book into which is gathered all the musical elements of the Mass; unlike a missal it does not contain spoken passages. It is sometimes called "the antiphonal of the Mass." In the Ege portfolios Leaves 08 and 32 are from graduals.
Lectionary: A book containing pre-assigned, scheduled readings from the Bible throughout the year. While the practice developed in Hebrew culture, the only Ege lectionary leaf (number 03) is Christian.
Missal: A book which contains the prayers said by the presiding priest, as well as texts that are read or sung by the congregation, during the celebration of the Mass throughout the ecclesiastical year. It emerged in the 13th century as a hybrid book containing what had up to that time been texts and music located in various specialized books like sacramentaries, antiphonals, and Bibles. Like many medieval liturgical manuscripts, missals have highly variable contents. In the Ege portfolios Leaves 02, 15, 22, 26, 33, 38, and 49 are from missals.
Psalter: A book containing readings from the Psalms and sometimes from other poetic sources such as Ecclesiastes or the Song of Songs. In the Ege portfolios Leaves 04, 10, 12, 17, 20, 25, 34, and 42 are from psalters.
Vulgate: The Bible translated into Latin from its original Greek and Hebrew; the word is most often used specifically to refer to the early fifth-century translation made by St. Jerome.