Today it's Celtic lore. ( info obtained from Wikipedia)
is a feminine spirit. She represents an omen of death and a
messenger from the Otherworld.
A banshee is a fairy who wails when someone is about to die.
The Banshee have been describes as women dressed in gray and having long hair. (From Wikipedia) The women are often seen brushing their hair with a silver comb. According to Irish legend, if you see a comb on the ground--NEVER pick it up, or the banshee will lure you away to the Otherworld.
I found these images of the Banshee online.
Fans of Rachel Vincent's Soul Screamers books will recognize the banshee as a main character in her books. For more information about the Soul Screamers, go here