Amalek

Amalek - dweller in a valley, the son of Eliphaz[?] and grandson of Esau (Gen. 36:12; 1 Chr. 1:36); the chief of an Idumean tribe (Gen. 36:16). His mother was a Horite, a tribe whose territory the descendants of Esau had seized.

From Easton's Bible Dictionary (1897)