Amalek in Fausset's Bible Dictionary

Son of Eliphaz, by his concubine Timnah, of the Horites; grandson of Esau; duke of Edom (Genesis 36:12; Genesis 36:16). The Edomites seized the Horite territory. In Hezekiah's reign, the last remnant of Amalek in Edom was dispersed by the Simeonites (1 Chronicles 4:42-43).

Link: https://bible-history.com/faussets/A/Amalek/