Esau: the firstborn twin of Isaac and Rebekah, the brother who sold his birthright, and the ancestor of the nation of Edom
The name belongs first to one man: the older of Isaac and Rebekah's twins, born gripping nothing while his brother יַעֲקֹב clutched his heel. The birth notice fixes two pictures to him at once. He comes out red and covered with hair, and the storyteller lets the name ring against the word for "hairy" and against the rugged land of שֵׂעִיר, the hill country where his descendants would settle. Then a second play lands over the birthright: when he trades it for a bowl of red stew, the text says that is why he was called "Red," which in Hebrew is אֱדוֹם, the name of the whole nation that came from him.
So the same name is worked in two directions, and every occurrence follows one of them:
- in the family stories it is the man himself, the hunter his father loved, the brother who wept for a stolen blessing and later ran to meet the runaway with open arms
- in the genealogies and the prophets it is the founding father of Edom, so that "Esau" and "Edom" become one people, and the prophets can even say "Mount Esau" for their homeland
That second use is why the name carries so much weight beyond Genesis. Long after the man is dead, the prophets keep saying "Esau" when they mean the nation to Israel's southeast, the near kin who turned hostile. The quarrel of the twins in the womb becomes the story of two peoples, and a reader who hears only the individual will miss what a verse like an oracle against "Esau" is actually about.
Where the name itself came from is a separate and unsettled question. Genesis is telling us what the name sounds like next to "hairy," "red," and Seir, not reporting a derivation, and scholars have never agreed on its origin. What is not in doubt is who he is: the twin of Jacob and the father of Edom.