TRIODION. - A liturgical book of the Byzantine rite, containing the Offices for the preparatory season of the feast of Easter, from the Sunday of the Publican and the Pharisee to Holy Saturday inclusive.
It is called T. because many of the canons contained in it have only three odes: the 8th and 9th always, and then one of the first five. It collects the compositions of some twenty poets, among whom Theodore and Joseph the Studites occupy a special place. The T. was first published in Greek in Venice in 1522, while the first Slavonic edition is that of Cracow from 1491.