Norse mythology knows of Light-elves (Liosálfar) who dwell in the third space in heaven, Dark-elves (Döckálfar) and Black-elves (Svartalfar), the Black-Elves being identifed with Dwarfs though in general Elves and Dwarfs are distinguished in surviving Norse literature. But about Elves (other than Black-elves/Dwarfs) little is said. They are often mentioned along with the gods, apparently as lesser spirits of nature.
So little has survived that we have no idea as to whether these beings were thought of as generally human-sized or dwarfish, though that the full size smith hero Völund is once called an elf indicates that not all Norse Elves need be of small size.
The term ćlfsciene 'Elf-shining' is used in the Old English poem Judith referring to Elven beauty. On the other hand oaf is simply a variant of the word elf, presumably originally referring to a changeling or to someone stupified by Elvish enchantment.
Supernatural folk were often pictured as living in forests and other natural places or underground or in wells and springs. They were imagined to be long-lived or immortal and magical powers were attributed to them.
Elf-shot was the name use for found neolithic flint arrow-heads, imagined as created and used by the Elvish folk and sudden paralysis was sometimes attributed to Elf-stroke.
Unfortunately we have little documentation of English rustic beliefs and terminology before the nineteenth century, but it seems Elves could be used, at least on some occasions or some places, to refer to various kinds of uncanny wights whether human sized or smaller. But other terms were also used.
However in Elizabeth England Shakespeare imagines Elves and Fairies in general as little people. In Henry IV, Part 1, i. 4, he has Falstaff call Prince Henry: "you starveling, you elfskin!" and in his Midsummer Night's Dream his Elves are almost as small as insects. On the other hand Edmund Spenser applies Elf to full-sized beings in his Fairie Queene.
But the influence of Shakespeare and Michael Drayton influenced the use of Elf and Fairy for very small beings to become the norm. In Victorian literature Elves usually appeared in illustrations as tiny men with pointed ears and stocking caps. There were exceptions such as the full-size Elves who appear in Lord Dunsany's The King of Elfland's Daughter. In 1954 Poul Anderson introduced grim Norse Elves in his fantasy novel The Broken Sword and made them full-sized.
Fairy (a word of French derivation) was the more general term in modern English for supernatural folk and more likely to be used for full sized supernatural beings, but it became spoilt for its proper use by being much used instead to mean 'effiminate' or 'homosexual''.
Probably partly for this reason as well as from a preference for native English words over foreign imports, the mid-twentieth-century fantasy writer J.R.R. Tolkien used Elves in his published fantasy as the name of an imagined race of beings similar to humans but fairer, with greater spiritual powers, more closely linked to nature and with lives as long as the earth would exist.
Those who still remain in mortal lands are supposed to have dwindled in size and faded to a wraith-like form and to have become the truth (or one of the truths) behind strange wights glimpsed in folklore. But Tolkien's works speak of his Elves when their race was still young and they were much like human beings and were ferocious warriors at need. Tolkien had little use for Shakepearian fairy protrayals, much less for Victorian diminutive fairy prettiness and whimsy. He used the earlier and less-used Elven rather than Edmund Spenser's invented Elfin as the corresponding adjective.
Tolkien's The Lord of the Rings, published in 1954, became astoundingly popular and was much imitated. In the 1960's and beyond "Elves" similar to those in Tolkien's writing became staple non-human characters in high fantasy works as well as in fantasy gaming which derived its origin mostly from role-playing games influenced by Tolkien's writing.
Accordingly post-Tolkien literary Elves tend to be human-sized or only slightly smaller than humans and capable warriors especially skilled in archery. (They are unlikely to sneak in at night and help a cobbler mend his shoes. Terms like Hob or Brownie or other genuine regional folklore terms are likely to be used of such creatures if they are written about.) Tolkien's Elves were enemies of the Goblins/Orcs and had a longstanding quarrel with the Dwarves and these motifs also often reappear.
Wendy and Richard Pini's long-running comic book Elfquest attempts to avoid the usual elfin clichés and Tolkien Elf clichés by placing their Elves in a setting inspired by Native American rather than European mythology.
Elf can mean an Earth Liberation Front sympathizer.
See also: ELF