||Esau said to Jacob, 'Give me a swallow of that red stuff! I'm famished!' (He was therefore given the name Edom).
Vayomer Esav el-Ya'akov hal'iteni na min-ha'adom ha'adom hazeh ki ayef anochi al-ken kara-shmo Edom.
||'First sell me your birthright,' replied Jacob.
Vayomer Ya'akov michrah chayom et-bechoratecha li.
Literally red. See Genesis 25:25. Also see Genesis 32:4, 36:1, 36:8, 36:19, etc. In later times, the Greeks called Edom, Idumia (Josephus, Antiquities 2:1:1).
This meant that Jacob would now be the primary heir and would also serve as the family priest (Rashi).