1) Medieval architecture 
The diaconicon (διακονικόν diakonikon; Slavonic: diakonik) is, in Eastern Orthodox and Eastern Catholic (`Uniate`) churches, the name given to a chamber on the south side of the central apse of the church, where the vestments, books, etc., that are used in the Divine Services of the church are kept (the sacred vessels are kept in the P.....
sacristy for sacred vessels in Orthodox churches
(from the article `sacristy`) ...objects used in the services are stored and in which the clergy and sometimes the altar boys and the choir members put on their robes. In the ...
a sacristy in an Eastern or early Christian church, usually on the south side of the bema.