Jahdai in the Bible Encyclopedia - ISBE
ja'-da-i, ja'-di (yahday, "Yah leads" (?); Baer reads yehday):
In 1 Ch 2:47, where six sons of Jahdai are mentioned. "The
name has been taken as that of another wife or concubine of
Caleb; more probably Jahdai is a descendant of Caleb, whose
name, in the original connection, has fallen from the text"
(Curtis, Chronicles, 96).
Jahdai in Wikipedia
Jahdai is a biblical figure that according to 1 Chron 2:47 is
either a concubine or a descendant of Caleb. the text is
ambiguous on the matter. 1 Chronicles 2:46-48 (Young's Literal
46And Ephah concubine of Caleb bare Haran, and Moza, and
Gazez; and Haran begat Gazez. 47And sons of Jahdai: Regem, and
Jotham, and Geshem, and Pelet, and Ephah, and Shaaph. 48The
concubine of Caleb, Maachah, bare Sheber and Tirhanah