A bog body is a human cadaver that has been naturally mummified in a peat bog. Such bodies, sometimes known as bog people, are both geographically and chronologically widespread, having been dated to between 8000 BCE and the Second World War. The unifying factor of the bog bodies is that they have been found in peat and are partially preserved; however, the actual levels of preservation vary widely from perfectly preserved to mere skeletons.

A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay further if kept in cool and dry conditions. Some authorities restrict the use of the term to bodies deliberately embalmed with chemicals, but the use of the word to cover accidentally desiccated bodies goes back to at least the early 17th century.