What is "eldarion"

Eldarion Telcontar is a fictional character from J. R. R. Tolkien's Middle-earth legendarium. He was the only recorded son of Arwen and Aragorn, born in the Fourth Age. He became the Second High King of the Reunited Kingdom of Gondor and Arnor after his father died.

"Eldarion" means "Son of the Eldar" or "Son of the Elves". He was also recorded as having at least two sisters.

Eldarion was descended from several royal Elven houses, including the Three High Kings of the Elves, and from the Edain. He was a grandson of Elrond and, through his grandmother Celebrían, a great-grandson of Galadriel. He was the great-grandson of Eärendil the Mariner (Eldarion is descended from Eärendil on both sides of his family and in him the two genealogical lines of the Half-elven are reunited), through his Half-elven mother Arwen; he was also the nephew of the Half-elf lords Elladan and Elrohir. He was descended also from the great Kings of Westernesse on his father's side.