Boyd’s Bible Dictionary:
(place-holders). Satraps or viceroys (Esther 8:36). Princes (Dan. 3:2; 6:1).
Concise Bible Dictionary:
Governors of districts in the Persian kingdom, otherwise known as satraps or viceroys (Ezra 8:36; Esther 3:12; Esther 8:9; Esther 9:3).