🔼The name Jesher in the Bible
There's only one Jesher in the Bible, and he's a son of Caleb the son of Hezron, son of Perez, son of Judah and Tamar. This Caleb is not the famous friend of Joshua but the only other Caleb mentioned in the Bible. Jesher plays no further role in the Bible, and the only additional info we have on him is that his mother is called either Azubah or Jerioth (we're not sure) and his brothers are Shobab and Ardon. Their half-brother Hur is a son of Ephrath.
🔼Etymology of the name Jesher
The name Jesher comes from the verb ישר (yashar), meaning to be straight:
For a meaning of the name Jesher, NOBSE Study Bible Name List reads Uprightness and Jones' Dictionary of Old Testament Proper Names has Upright, or Just.