Pronunciation: (ek'särk),[key] —n. 1. Eastern Ch. a. a patriarch's deputy.
b. a title originally applied to a patriarch but later applied only to a bishop ranking below a patriarch and above a metropolitan.
2. the ruler of a province in the Byzantine Empire.
Pronunciation: (ek'särk),[key] —adj.Bot. (of a primary xylem or root) developing from the center; having the youngest cells closest to the core.