the South Slavic language used in the 9th-cent. Bible translation by Saint Cyril and his brother, Saint Methodius, and still used as a liturgical language (now called Church Slavonic) by Orthodox Slavs but extinct as a vernacular
See Old Church Slavonic in American Heritage Dictionary 4
The medieval Slavic language used in the translation of the Bible by Cyril and Methodius and in early literary manuscripts and still used as a liturgical language by several churches of Eastern Orthodoxy. Also called Church Slavonic, Old Bulgarian.