A bogle, boggle, or bogill is a Northumbrian and Scots term for a ghost or folkloric being, used for a variety of related folkloric creatures including Shellycoats, Barghests, Brags, the Hedley Kow and even giants such as those associated with Cobb's Causeway (also known as "ettins", "yetuns" or "yotuns" in Northumberland and "Etenes", "Yttins" or "Ytenes" in the South and South West). They are reputed to live for the simple purpose of perplexing mankind, rather than seriously harming or serving them.

The name is derived from the Middle-English Bugge (from which the term bogey is also derived) which is in turn a cognate of the German term word bögge (from which böggel-mann ("Goblin") is derived) and possibly the Norwegian dialect word bugge meaning "important man". The Welsh Bwg could also be connected, and was thought in the past to be the origin of the English term; however, it has been suggested that it is itself a borrowing from Middle English.

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