NONA. – This is that part of the Divine Office which is recited at the ninth hour (= 3 p.m.), according to the Greco-Roman division of the day. This hour of prayer, already used in the Synagogue (cf. Dan. 6, 10; Ps. 54, 18), passed into Christian usage (Act. 3, 1; cf. 2, 15; 10, 9) as a private prayer for sanctifying the day (Didaché, cap. 8, 3; Tertulliano, De oratione, 23; De ieiunii, cap. 10; Cost. apost., cap. VIII, n. 34, 1); as a canonical hour reserved for monks, it was in use in the fourth century. During the fifth century it was also introduced into the daytime Office of the basilicas of the City.
It consists of the hymn (originally absent from the Roman Office), three Psalms (the number three already being used by the monks of Egypt), a lesson followed by a responsory (in the Roman Office), a versicle, and the concluding prayer.
Various relationships between the individual daytime hours and certain moments of Christ’s Passion and the life of the Apostles were established by the early writers (Ippolito, Costitua. apostoliche, Cipriano, and others), but the Church did not adopt them, except in the case of the hymn of Terza. There is, however, a special relationship between the daytime hours and the Holy Mass: on feasts and Sundays the conventual Mass is said after Terza, on weekdays after Sesta, and during times of fasting and penance (Advent, Lent, Vigilia) after N. In the latter two cases, Sesta and N. are anticipated before noon.