Easton's Bible Dictionary

Keturah - incense, the wife of Abraham, whom he married probably after Sarah's death (Gen. 25:1-6), by whom he had six sons, whom he sent away into the east country. Her nationality is unknown. She is styled "Abraham's concubine" (1 Chr. 1:32). Through the offshoots of the Keturah line Abraham became the "father of many nations."