His name in Quenya means "Scion of the Eldar". In Letter 338, J.R.R. Tolkien spelled this name Eldaron, this is probably a typographic error.
Quenya
eldarion
masculine name. *Son of the Eldar
Elements
Word Gloss Elda “Elf, (lit.) one of the Star-folk” -ion “-son, masculine patronymic”
Eldarion
Eldarion
The son of Aragorn and Arwen (LotR/1062). His name is a compound Eldar “Elves” and the patronymic suffix -ion “-son”.