Banshee

Banshee is a shapeshifting fairy that, according to Irish myth and legend, is usually seen as a floating old hag or young, fair woman and is the most feared because she is believed to forewarn the death of a person with her piercing scream. She was usually accompanied by the Dullahan who was a headless fairy on a horse. "Originally in Irish literature, banshee actually means "woman of fairy mound" or just simply as "fairy woman". Ban or bean meaning "woman". The various spelling or pronounciation of the word for fairy mound referred to the Otherworldly realm, which the Irish referred to as shee, sid,sidh or sidhe. word banshee may have originated from East Munster, and there are many ways it can be spelt. In Irish Gaelic it could be spelt as banshie,bean sidhe and ben side. The Scottish words are ban-sith, bean-shith and bean sith. The Manx form is ben shee." (Jimmy) It is believed by celtic mythology that the Banshee myth was "developed due to the Irish tradition of the lament; women would sing a lament for the dead at funerals, and for some in the village, this song would carry through the air and become the first signal that someone had died." (O'Brien)

References 

"Fairy And Fairy Tale." (n.d.): Funk & Wagnalls New World Encyclopedia. Web. 6 Dec. 2012.

Jimmy, Joe. "Faeries." Timeless Myths. N.p., 1999. Web. 06 Dec. 2012.

O'Brien, Ciara. "Irish Mythology: The Banshee." Irish Mythology: The Banshee. Irish Celtic Jewels, 27 Apr. 2010. Web. 06 Dec. 2012.

Rose, Carol. Spirits, Fairies, Leprechauns, and Goblins: An Encyclopedia. W. W. Norton & Company, 1998. Print.