a female spirit in Irish mythology who heralds the death of a family member, usually by shrieking or keening.
The banshee is often described in Gaelic lore as wearing red or green, usually with long, disheveled hair (usually described as red or orange, and yellow in medieval times described to shimmer like wild fire).
She can appear in a variety of forms.
Perhaps most often she is seen as an ugly, frightful hag, but she can also appear young and beautiful if she chooses.
In some tales, the figure who first appears to be a banshee or other cailleach (hag) is later revealed to be the Irish battle goddess, Morrígan.