Mareridt means 'nightmare', and as in English, it can be used both to describe a bad dream, and figuratively, to describe a highly negative experience or mareridtscenarie (‘nightmare scenario’). As to this first part of the word, the old Norse word mara used to refer to a spirit or demon, usually believed to be female, which people thought was responsible for causing bad dreams. While the Swedish word for nightmare, mardröm, uses the modern word for dream, in Danish it’s ridt, not drøm, which forms the second part of this word.