Eldar (singular Elda) was the name given to the Elves (and the term West Elves may also apply to these kindred) by the Vala Oromë when he first found them wandering in the starlight of Cuiviénen. At first, the name was applied to all Elves, but after the summons of the Valar, it came to be used only of the peoples who followed the summons and began the Great Journey.
Many of the Teleri also journeyed to Valinor, but twice a host of this people turned away from the Journey in Middle-earth; these two kindreds are called Úmanyar, the Eldar not of Aman. The first of these were the Nandor, who turned aside east of the Misty Mountains, and travelled down the River Anduin. The second, the Sindar, tarried in Beleriand seeking their lord, Elwë Singollo.
Eldar is both a common Hebrew name meaning "god resides" and a rare Norse first name meaning "Fire Warrior" (Eld+Harjar))