A fairy (also fay, fae; from faery, faerie, "realm of the fays") is a type of mythical being or legendary creature in European folklore, a form of spirit, often described as metaphysical, supernatural, or preternatural.
Fairies resemble various beings of other mythologies, though even folklore that uses the term fairy offers many definitions. Sometimes the term describes any magical creature, including goblins or gnomes: at other times, the term describes only a specific type of more ethereal creature or sprite. Various folkloristic traditions refer to them euphemistically, by names such as wee folk, good folk, people of peace, fair folk (Welsh tylwyth teg), etc.
Much of the folklore about fairies revolves around protection from their malice. Although in modern culture they are often depicted as young, sometimes winged, humanoids of small stature, they originallywere depicted quite differently: tall, radiant, angelic beings or short, wizened trolls being two of the commonly mentioned forms.
One common theme found among the Celtic nations describes a race of diminutive people who had been driven into hiding by invading humans. When considered as beings that a person might actually encounter, fairies were noted for their mischief and malice.
Fairies are generally described as human in appearance and having magical powers. Their origins are less clear in the folklore, being variously dead, or some form of demon, or a species completely independent of humans or angels.
The concept of "fairy" in the narrow sense is unique to English folklore, conflating Germanic elves with influences from Celtic and Romance (French) folklores, and later made "diminutive" according to the tastes of Victorian era "fairy tales" for children. The English term "fairy" can be applied to comparable beings in any of these cultures, more generally to similar beliefs in other European folklores ("Slavic fairies"), or in comparative studies even worldwide.
Fairies have their historical origin in the conflation of Celtic (Breton, Welsh) traditions in the Middle French medieval romances, e.g. as one of the beings that a knight errant might encounter. Fairie was in origin used adjectivally, meaning "enchanted" (as in fairie knight, fairie queene), but was used as a name for "enchanted" creatures from as early as the Late Middle English period.
Fairies as the term is now understood were shaped in the literature of Romanticism during the Victorian era. Writers such as Walter Scott and James Hogg were inspired by folklore which featured fairies, such as the Border ballads.
Folklorists have suggested that their origin may lie partially in a conquered race living in hiding, or in religious beliefs that lost currency with the advent of Christianity.