E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Elf (plural, Elves, Anglo-Saxon, lf).
Properly, a mountain fay, but more loosely applied to those airy creatures that dance on the grass or sit in the leaves of trees and delight in the full moon. They have fair golden hair, sweet musical voices, and magic harps. They have a king and queen, marry and are given in marriage. They impersonate the shimmering of the air, the felt but indefinable melody of Nature, and all the little prettinesses which a lover of the country sees, or thinks he sees, in hill and dale, copse and meadow, grass and tree, river and moonlight. Spenser says that Prometheus called the man he made Elfe, who found a maid in the garden of Adonis, whom he called Fay, of whom all Fayres spring.
Of these a mighty people shortly grew,
And puissant kings, which all the world warrayd,
And to themselves all nations did subdue.
Faërie Queene, ii. 9, stanza 70. etc.
Elf and Goblin, as derived from Guelf and Ghibelline, is mentioned in Johnson (article GOBLIN), though the words existed long before those factions arose. Heylin (in his Cosmography, p. 130) tells us that some supported that opinion in 1670. Skinner gives the same etymology.
Red Elf. In Iceland, a person gaily dressed is called a red elf (raud âlfr), in allusion to a superstition that dwarfs wear scarlet or red clothes. (Nials Sagas.) Black elves are evil spirits; white elves, good ones.