🔼The name Ithamar in the Bible
There's only one Ithamar in the Bible and he is one of the four sons of Aaron the brother of Moses and Miriam, and his wife Elisheba, the daughter of Amminadab. Ithamar's brothers are called Nadab, Abihu and Eleazar (Exodus 6:23).
Since the priesthood and the high-priesthood was an exclusive asset of the descendants of Aaron, the sons of Aaron not only became clan-heads but also the patriarchs of distinct categories in the priesthood (Exodus 28:1, Exodus 38:21). Nadab and Abihu, however, came to their untimely demise when they offered "strange fire" before YHWH and they died childless because of that (Leviticus 10:1, Numbers 3:4). Moses told the remaining sons of Aaron, Ithamar and Eleazar, to not even mourn their brothers' deaths.
When the worship service began to take shape, Ithamar would direct the Gershonites (Numbers 4:28) and the sons of Merari (Numbers 4:33). During the time of David, the duties pertaining to the "officers of the sanctuary and officers of God" were divided over the descendants of Ithamar and Eleazar (1 Chronicles 24:5). At the time of the exile this division was still in tact, as Ezra lists among those who returned with him a man named Daniel "of the sons of Ithamar" (Ezra 8:2).
🔼Etymology of the name Ithamar
The name Ithamar could be construed as to consist of two elements. The first one would be the multifarious word אי ('i):
The second part of our name looks strikingly like the noun תמר (tamar), meaning palm tree:
For a meaning of the name Ithamar, NOBSE Study Bible Name List proposes Island Of Palms and Jones' Dictionary of Old Testament Proper Names reads Land Of Palm. BDB Theological Dictionary, in its signature trepid form, keeps all options open and reads (Is)land Of Palms?.