Aos Sí

Aos sí (pronounced [iːsˠ ˈʃiː]; English approximation: /iːs ˈʃiː/ eess SHEE; older form: aes sídhe [eːsˠ ˈʃiːə]) is the Irish name for a supernatural race in Celtic mythology – daoine sìth in Scottish Gaelic – comparable to fairies or elves. They are said to descend from the Tuatha Dé Danann, meaning the 'People of Danu', depending on the Abrahamic or pagan tradition.

The aos sí are said to live underground in fairy forts, across the Western sea, or in an invisible world that co-exists with the world of humans. This world is described in the Lebor Gabála Érenn as a parallel universe in which the aos sí walk among the living.

In modern Irish the people of the mounds are also called daoine sí; in Scottish Gaelic they are called daoine sìth (in both cases, it means 'people of the fairy mound'). They are variously said to be the ancestors, the spirits of nature, or goddesses and gods.