The "Fae" Tradition is a whole belief system.
according to Wikipedia
"A fairy (also fay, fae, fair folk; 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."
According to Thomas Keightley, the word "fairy" derives from the Latin fata, and is from the Old French form faerie, describing "enchantment". Other forms are the Italian fata, and the Provençal "fada". In old French romance, "fee" was a woman skilled in magic, and who knew the power and virtue of words, of stones, and of herbs.[1]
Faie became Modern English fay. Faierie became fairy, but with that spelling now almost exclusively referring to one of the legendary people, with the same meaning as fay. The word "fairy" was used to in represent an illusion, or enchantment; the land of the Faes; collectively the inhabitants thereof; or an individual such as a fairy knight.[1]
To the word faie was added the suffix -erie (Modern English -(e)ry), used to express either a place where something is found (fishery, nunnery) or a trade or typical activity engaged in (cookery, thievery). In later usage it generally applied to any kind of quality or activity associated with a particular type of person, as in English knavery, roguery, wizardry. In the sense "land where fairies dwell", the distinctive and archaic spellings Faery and Faerie are often used.
The latinate fay is not to be confused with the unrelated (Germanic) fey, meaning "fated to die".[2]
Various folkloristic traditions refer to them euphemistically, by names such as wee folk, good folk, people of peace, fair folk (Welsh tylwyth teg), etc.[3]
Sometimes the term fairy is used to describe any magical creature, including goblins or gnomes: at other times, the term describes only a specific type of more ethereal creature or sprite.[4]
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.
Fairies have their historical origin in the conflation of Celtic (Breton, Welsh) traditions in the Middle French medieval romances.
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.In English literature of the Elizabethan era, elves became conflated with the fairies of Romance culture, so that the two terms began to be used interchangeably.
Hope this helps
https://en.wikipedia.org/wiki/Fairy