🔼The name Timnath-serah in the Bible
The name Timnath-serah occurs twice in the Bible. It is the name of the city in Ephraim, north of Mount Gaash, that was assigned to Joshua (Joshua 19:50). The text reads that YHWH commanded the Israelites to give Joshua a city, but that command doesn't seem to be recorded elsewhere. The wording seems to suggest that Joshua was given an existing village which he expanded and fortified and settled. When Joshua died, he was buried in the land associated to the city he had constructed (Joshua 24:30), and which was also known as Timnath-heres (Judges 2:9).
🔼Etymology of the name Timnath-serah
The name Timnath-serah obviously consists of two elements. The first part of our name comes from the verb מנה (mana) meaning to count or to assign:
The second part of our name appears to be the noun סרח (serah), meaning excess:
BDB Theological Dictionary suggests that the name Timnath-serah may have been constructed from the name Timnath-heres by swapping the letters of the second part around (this is called metathesis, and seems to have been an acknowledged literary tool in ancient times). The name Timnath-heres means Territory Of The Sun and was probably named with sun worship in mind. Since it was Joshua's town, and Joshua was a man of God, scribes may have wanted to avoid the risk of inadvertently associating Joshua with pagan worship. Of course, we don't know if any of this is even remotely true or relevant.
For a meaning of the name Timnath-serah, NOBSE Study Bible Name List reads Extra Portion. Jones' Dictionary of Old Testament Proper Names proposes Portion Redundant and Abundant Portion. BDB Theological Dictionary doesn't interpret this name beyond its suggestion of its metathetic relation to Timnath-heres.