“Many people believe that it is from her wings* and her Gaelic name, Eilean Sgiathanach (Winged Isle), that the name Skye comes. Ptolemy of Alexandria (A.D. 200) refers to the island as Sketis, while the ancient Celtic name ‘Skeitos’ has become Sgiath in modern Gaelic. Adamnan knew it as Scia. This ‘wing derivation certainly sounds very probable, more probable than the other version which claims that ‘Skye’ is Scandinavian, derived from a norse word Ski (cloud). This school of thought takes its stand on the fact that cloud or mist is what would first and most forcibly attract the notice of any stranger visiting the isle**, whereas to notice the ‘wings’ requires a map. Obviously this school has never tried (as the early Scandinavian settlers most certainly did) to sail around the despised wings. Of course, many place-names in Skye undoubtedly are Scandinavian, but they date from a later time than Ptolemy – four or five centuries later. A third suggestion, once seriously put forward by certain Celtic antiquaries, was that in Skye stood the temple, known to Greek fable, of Apollo among the Hyperboreans, and that the Gaelic name of the island refers to the wings of the Greek god! The name may, in fact, belong to some old forgotten pre-Celtic tongue.”
- Otta F. Swire, Skye: The Island and its Legends, 1961, pp. 72-3.
* The “wings” are Skye’s various promontories, for example Trotternish, Waternish and Duirnish.
** Skye is also known as Eilean a’ Cheò, meaning “The Misty Isle”.
As far as I know, it was Callanais that was put forward as the temple of the hyperborean Apollo. I also thought Sgaith came from Scathach, the legendary warrior woman whose name means "Shadowy". She ran a famous warrior school there where Cu Chullain learned warcraft and "the friendship of her thighs". There are a lot of other names on the island with connections to this legend.