🔼The name Sheshai in the Bible
There's only one Sheshai in the Bible, and he is one of the three gargantuan sons of Anak (Numbers 13:22). His brothers were named Ahiman and Talmai, and they lived in Hebron. The city of Hebron was given to Caleb, and he drove out the three brothers (Joshua 15:14).
Whether they managed to slip back in, or whether they remained to be known as the Canaanites of Hebron isn't clear, but the book of Judges reports a campaign that took place after the death of Joshua, during which the tribe of Judah warred against the Canaanites of Hebron and killed them and the three sons of Anak (Judges 1:10).
🔼Etymology of the name Sheshai
The origin of the name Sheshai could probably be traced back to the following word cluster:
The letter י (yod) upon which our name ends, may either create an adjective (whitish or pale), a possessive form (my lily), or may be a remnant of יה (Yah) = יהו (Yahu) = יו (Yu), which in turn are abbreviated forms of the Tetragrammaton יהוה, YHWH, or Yahweh.
For a meaning of the name Sheshai, both NOBSE Study Bible Name List and Jones' Dictionary of Old Testament Proper Names take the final yod to mark an adjective and read Whitish. BDB Theological Dictionary does not offer an interpretation of this name.