🔼The name Reu in the Bible
Reu is a son of Peleg the brother of Joktan; the two arch-fathers of the Shemite divide (Genesis 11:18). Reu's son is Serug, and his grandson is Nahor, the grandfather of Abraham. Reu is therefore also an ancestor of David and ultimately of Jesus Christ (Luke 3:35, curiously spelled Ραγαυ, Ragau), but also see the name Reuel, which in the Greek Septuagint appears as Ραγουηλ, Raguel.
🔼Etymology of the name Reu
BDB Theological Dictionary reports that Reu is the name of an ancient god, so maybe Peleg named his son after him. Be that as it may, the way Reu is spelled leads to suspect relations with the root group רעה (ra'a I, II & III):
For a meaning of the name Reu, NOBSE Study Bible Name List reads Friend and Jones' Dictionary of Old Testament Proper Names proposes Associate.