JOKTAN (jŏk'tăn, Heb. yoqtān, meaning unknown). A tribe descended from Shem through Eber and from whom thirteen tribes of Arabia subsequently descended (Gen.10.25-Gen.10.26, Gen.10.29; 1Chr.1.19-1Chr.1.20, 1Chr.1.23).
JOKTAN jŏk’ tăn (יָקְטָֽן). A son of Eber and a brother of Peleg and from whom thirteen tribes of Arabia sprang (Gen 10:25-29; 1 Chron 1:19-23). It is said that his descendants lived from Mesha to Sephar. It is apparent that he was the ancestor of the older Arabian tribes.
International Standard Bible Encyclopedia (1915)
"Son" of Eber, and "father" of 13 tribes (Ge 10:25,26,29; 1Ch 1:19,20,23).