Aldamir is Quenya, from alda meaning "tree", and mírë meaning "jewel".
Quenya
aldamir
masculine name. *Tree Jewel
Elements
Word Gloss alda “tree, tree, [ᴱQ.] branch” mírë “jewel, gem, precious thing, treasure; precious”
Aldamir
Aldamir
The 23rd king of Gondor (LotR/1038). His name seems to be a compound alda “tree” and mírë “jewel”.