🔼The name Rehabiah in the Bible
There's only one Rehabiah in the Bible, and he is a son of Eliezer and grandson of Moses (1 Chronicles 23:17). The Chronicler distinguishes Rehabiah for having a great many sons but names none of them, except Isshiah "the first" or "the chief" (1 Chronicles 24:21).
Our name is spelled with a final waw (רחביהו) in 1 Chronicles 24:21 and 26:25. It's very common for names that end with יה to also exist ending on יהו.
🔼Etymology of the name Rehabiah
The name Rehabiah consists of two elements, the final one being יה (Yah) = יהו (Yahu) = יו (Yu), which in turn are abbreviated forms of the Tetragrammaton יהוה, YHWH, or Yahweh.
The first part of our name comes from the verb רחב (rahab), meaning to be wide:
For a meaning of the name Rehabiah, NOBSE Study Bible Name List reads Yahweh Is Wide and Jones' Dictionary of Old Testament Proper Names has Enlarging Of The Lord. BDB Theological Dictionary doesn't interpret the name Rehabiah but does list it under the verb רחב (rahab), meaning to be wide.