'banshee' originates from Irish Gaelic, specifically the phrase 'bean sí' or 'bean sídhe', where 'bean' meant 'woman' and 'sí(dhe)' meant 'fairy' or 'mound (of the fairies)'.

'banshee' was borrowed into English from the Irish 'bean sí(dhe)' (literally 'woman of the sí'), being anglicized in spelling and pronunciation to the modern English word 'banshee'.

Initially it referred specifically to the 'woman of the sí'—a fairy woman associated with a particular household— and over time it retained the core idea of a supernatural female that heralds death; it later also gained a figurative sense for someone who wails loudly.