- A bishop in the Eastern Orthodox Church ranking immediately below a patriarch.
- The ruler of a province in the Byzantine Empire.
- The ruler of a province in the Byzantine empire. The most important was the exarch of Ravenna. See <internalXref urlencoded="exarchate">exarchate</internalXref>.
- In the <em>early church</em>, a prelate presiding over a diocese: as, the <em>exarch</em> of Ephesus. The title is often used as synonymous with <em>patriarch</em>; but strictly the exarch was inferior in rank and power to the patriarch, and superior to the metropolitan.
- In the <em>Gr. Ch.</em>, a legate of a patriarch, whose duty it is to sustain the authority of the patriarch, and to obtain accurate information concerning the lives of the clergy, ecclesiastical observances, monastic discipline, etc., in the provinces assigned to him. The power of the exarchs is very great. They can absolve, depose, or excommunicate in the name of the patriarch.
- A viceroy; in Ravenna, the title of the viceroys of the Byzantine emperors; in the Eastern Church, the superior over several monasteries; in the modern Greek Church, a deputy of the patriarch , who visits the clergy, investigates ecclesiastical cases, etc.
- In the Byzantine Empire, a <xref>governor</xref> of a distant <xref>province</xref>.
- In the Eastern Christian Churches, the <xref>deputy</xref> of a <xref>patriarch</xref>, or a <xref>bishop</xref> who holds authority over other bishops without being a patriarch.
- In these same churches, a bishop appointed over a group of the <xref>faithful</xref> not yet large enough or organized enough to constitute an <xref>eparchy</xref> or <xref>diocese</xref>.
- a bishop in one of several Eastern Orthodox Churches in North America
- a bishop in eastern Christendom who holds a place below a patriarch but above a metropolitan
- a viceroy who governed a large province in the Roman Empire