The word banshee was first used in the English language in a 1771 book about Scotland, where it was spelled benshi. For the next century or so, all kinds of spellings were attested, such as ben-shie and banshie, but by the late ninetenth century the form banshee was widely accepted. The word is a phonetic transcription of the Irish term bean sidhe, meaning "female elf" or, more literally, "woman of the fairy mound". Bean is from ben, which is from Proto-Celtic bena and Proto-Indo-European gwen, also meaning "woman" (and the root of words as diverse as queen and gynecology). Sidhe is from Proto-Celtic sidos, which could just mean "mound" but definitely still had connotations of fairies, and that derives from Proto-Indo-European sed, "to sit". Usage of the word banshee has been increasing since the 1980s.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.