1) the office of a governor or prefect
2) the region subject to a prefect
2a) a province of the Roman empire, either a larger province, or an appendage to a larger province, as Palestine was to that of Syria
Part of Speech: noun feminine
From a compound of G1909 and G757 (meaning a governor of a district, "eparch"); a special region of government, that is, a Roman praefecture: - province.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root ἐπαρχεία; click on the second column to search for that grammatical form of the root ἐπαρχεία; click on the third column to search for that word and grammatical form; click on the total to search for the root ἐπαρχεία.