Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
In 1 Ki. 22:47, means a prefect; one set over others. The same Hebrew word is rendered "officer;" i.e., chief of the commissariat appointed by Solomon (1 Ki. 4:5, etc.).
In Esther 8:9, 9:3 (R.V., "governor") it denotes a Persian prefect "on this side" i.e., in the region west of the Euphrates. It is the modern word pasha.
In Acts 13:7, 8, 12, 18:12, it denotes a proconsul; i.e., the governor of a Roman province holding his appointment from the senate. The Roman provinces were of two kinds,
The appointment of a governor to the former was in the hands of the senate, and he bore the title of proconsul (Gr.anthupatos). The appointment of a governor to the latter was in the hands of the emperor, and he bore the title of propraetor (Gr.antistrategos).