Diaconicum (Gr. and Lat.). This word has different significations in ecclesiastical authors. Sometimes it is taken for that part of the ancient church in which the deacons used to sit during the performance of divilfe service, namely, at the rails of the altar; sometimes for a building adjoining to the church, in which the sacred vessels and habits were laid up; sometimes for that part of the public prayers which the deacons pronounced. Lastly, it denotes an ecclesiastical book, in which are contained all things relating to the duty and office of a deacon, according to the rites of the Greek Church.