"bogy, hobgoblin, ghost." A solitary household fairy in Welsh tradition. It may be helpful, mischievous, or awesome for the household. In return for its help the bwci expects food, such as milk and bread but if these offerings are forgotten or tampered with, it will turn into a vengeful apparition.
- MacKillop, James. (2004). Dictionary of Celtic Mythology. New York: Oxford University Press, Inc.