Bansídhe (also banshee) is among the most internationally recognised of Irish supernatural figures, and her persistence in global culture has somewhat obscured the depth of her literary significance in the Irish tradition. She is simultaneously a mourner, a death-omen, a woman of the fairy world, and a figure of terrible, overwhelming grief. In poetry she merges the caoineadh tradition with the sídhe mythology, making her lament a bridge between human and supernatural worlds. Revival poets were drawn to her as an image of Ireland's own wailing grief — a country whose losses have been so great that the supernatural world itself weeps in sympathy.

Bansídhe is an alternative spelling of bean sídhe, emphasizing the phonetic pronunciation often heard in oral tradition. In poetic contexts, this spelling may be chosen to reflect dialectal variations or to create specific rhythmic effects. The bansídhe is distinct from general fairy folk because her primary function is mourning; she is attached to specific old families and her wail is a definitive omen of death. Poets use her image to explore themes of fate, ancestral guilt, and the inescapable presence of the past in the present.