Nightmare is one of my favourite English words when it comes to its etymology. And it’s origins are sadly not known by the average English speaker and sometimes they are even misunderstood.

Where does the word actually come from? Isn’t a ‘mare’ just a horse? What do horses have to do with bad dreams? Let’s immerse ourselves in a new etymological journey to find out!

Let’s start with the obvious – the word Nightmare looks like a compound word where one of the components is the word night.

Now, what does that second component of the word mean? A mare is just the female of a horse, you might say. And, while you’re not wrong, you kind of are.

This ‘mare‘ comes from the Old English Meare, which comes from the Proto-Germanic *marhijo-, its meaning is ‘a female horse‘, and this word is, contratry to what some people might believe, in no way related to the word nightmare.

The actual ‘mare‘ that is related to the word nightmare is that one whose origins lie in the Old English word mære, from the Proto-Germanic *maron.

This second ‘mare’ means something like a goblin, a monster, and it is a cognate to the German Mahr, the Dutch merrie, the Danish mare, the Swedish mara, the Norwegian mare,  the Icelandic mara and the Faroese marra.

The mare is found in Germanic and Slavic folklore and it is not just a simple goblin or monster, but raher an evil creature that rides people’s chests while they sleep, inducing bad dreams.

The Nightmare, Oil on Canvas by Henry Fuseli, 1781

The word nightmare now has a slightly creepier connotation after knowing this, doesn’t it? And most interesting is that English is not the only language that uses the word mare when referring to a bad dream.

In German we can find the old word Nachtmahr, nightmare, and the word Alptraum, Elven-dream; the latter with a similar principle like that of the word nightmare.

The Icelandic word martröð also means mare-dreaming, similar to the Swedish mardröm, a mare-dream.

In Norwegian the word mareritt and the Danish, mareridt, both mean mare-ride, alluding to the fact that mares ride their victims’ chests in the night to cause them bad dreams.


So now, everytime you hear someone saying they had a nightmare, you will know that it was most probably caused by a night demon. But I’d advise you against telling anyone, or else they’ll have even more nightmares!