Banshee anglicizes the Irish bean sídhe, a compound of two ancient words. Bean means "woman," descending from Old Irish ben, from Proto-Celtic *bena, ultimately from the Proto-Indo-European root *gʷen- ("woman, wife") — the same root that gives English "queen" (via Germanic *kwēniz) and Greek gynē ("woman," source of "gynecology"). Sídhe refers to the fairy mounds — the prehistoric burial cairns and passage tombs that dot the Irish landscape, believed to be entrances to the otherworld where supernatural beings dwelt.
The sídhe (also spelled sí in modern Irish) are central to Irish mythology. The Tuatha Dé Danann, the mythological race of gods who preceded the Gaels in Ireland, were said to have retreated into the sídhe mounds after their defeat, becoming the aos sí ("people of the mounds") — the fairy folk. The banshee is thus not a ghost in the Christian sense but a being from this pre-Christian otherworld, an emissary between the living and the dead.
In traditional belief, certain aristocratic Irish families were attended by their own banshee, whose keening (from Irish caoin, "to weep, lament") foretold the death of a family member. The sound was said to be heard even when the death occurred far from home. Accounts describe the banshee variously as a beautiful young woman, a stately matron, or a haggard old crone — corresponding perhaps to the triple goddess of Celtic mythology. She was sometimes seen washing bloodstained garments at a ford, a motif
The anglicization of bean sídhe to "banshee" reflects the phonetics of Munster Irish pronunciation, where the compound sounds roughly like "ban-shee." The word entered English literature primarily through 18th-century accounts of Irish folklore, though the figure had been described in Irish-language texts for centuries. The 1771 attestation in English marked the beginning of the banshee's career as one of the most recognizable figures in the English-speaking world's supernatural vocabulary.
In modern usage, "banshee" has largely detached from its specific Irish context. "Screaming like a banshee" is a common simile for any piercing shriek. The word has been adopted into popular culture — video games, films, and fantasy literature — though often stripped of the cultural specificity that made the original figure so compelling: a being whose cry was not malicious but mournful, a supernatural grief preceding inevitable loss.