Genesis 36:15 - Coke's Commentary on the Holy Bible

These were dukes— Leaders, or praefects; heads of their respective clans or families. As ףּאל signifies a thousand, as well as a leader, it is probable, that when mankind at the beginning were divided under distinct leaders, this (a thousand) was the number of men of which each government or state consisted: as we find here, that some of the sons of Esau were אלופים aluphim, heads of thousands, before there was a king.