Midian: a son of Abraham by Keturah, the desert people traced back to him, and the dry country east of the Gulf of Aqaba where they ranged
The name begins with one man. Genesis lists Midian among the sons Abraham had by Keturah, the wife he took after Sarah died, which makes the people who carry the name distant relatives of Israel on Abraham's side. From there the word spreads the way a family name can spread, until the same spelling covers the man, the tribes who trace themselves back to him, and the dry country they moved through with their flocks, somewhere south and east of Edom along the eastern side of the Gulf of Aqaba.
The sentence around the name is what tells you which of those is meant:
- the country Moses escapes into after killing the Egyptian is "the land of Midian", a place on a map
- the man who takes him in and gives him a daughter to marry is "the priest of Midian", so the name is a people with its own worship
- the force that settles in the valley every harvest is "the camp of Midian", an army with kings and chiefs
- and later writers say "the day of Midian" and mean one battle and how it ended
What unsettles readers is that the Bible tells two very different stories about the same people. In Exodus, Midian is a refuge: Moses works there for years, marries there, and after the escape from Egypt takes advice from his Midianite father-in-law on how to govern. A few books later Midian is the enemy. Numbers has Midianite women drawing Israel into the worship at Peor and Israel taking revenge; Judges has Midian riding in on camels alongside Amalek (עֲמָלֵק) and the people of the east, stripping the harvest year after year, until Gideon breaks them with three hundred men. The text never smooths the two pictures together.
That rout became a fixed point of reference. A psalm asking God to act and two of Isaiah's promises reach back to it, the way we might name a famous battle, to mean a rescue that came suddenly and with all the odds wrong. One individual from Midian is named by a related word (מִדְיָנִי), which is how Moses's wife and her family are described; this name is the collective one.