|Easton's Bible Dictionary|
Probably a poetic or prolonged name of the land of Cush, the Arabian Cush (Habakkuk 3:7). Some have, however, supposed this to be the same as Chushan-rishathaim (Judges 3:8, 10), i.e., taking the latter part of the name as a title or local appellation, Chushan "of the two iniquities" (= oppressing Israel, and provoking them to idolatry), a Mesopotamian king, identified by Rawlinson with Asshur-ris-ilim (the father of Tiglathpileser I.); but incorrectly, for the empire of Assyria was not yet founded. He held Israel in bondage for eight years.
Int. Standard Bible Encyclopedia
kushan: In the psalm of Habakkuk (Habakkuk 3:7) "the tents of Cushan" are mentioned in an individualizing description of the effects of a theophany. Parallel is the phrase "the curtains of the land of Midian." Septuagint renders Cushan, kushan, by Aithiopon, reading perhaps kushim, or kushin (kushin). The context indicates that the same land or people is intended as the Old Testament elsewhere calls Cush, yet vaguely and not in any strict geographical usage that would limit it to Africa.
Cushan (3 Occurrences)
Judges 3:8 Therefore the anger of Yahweh was kindled against Israel, and he sold them into the hand of Cushan Rishathaim king of Mesopotamia: and the children of Israel served Cushan Rishathaim eight years. (WEB JPS ASV BBE NAS NIV)
Judges 3:10 The Spirit of Yahweh came on him, and he judged Israel; and he went out to war, and Yahweh delivered Cushan Rishathaim king of Mesopotamia into his hand: and his hand prevailed against Cushan Rishathaim. (WEB JPS ASV BBE NAS NIV)
Habakkuk 3:7 I saw the tents of Cushan in affliction. The dwellings of the land of Midian trembled. (WEB KJV JPS ASV BBE DBY WBS YLT NAS RSV NIV)