Did you know?
Looking at nightmare, you might guess that it is a compound formed from night and mare. If so, your guess is correct. But while the night in nightmare makes sense, the mare part is less obvious. Most English speakers know mare as a word for a female horse or similar equine animal, but the mare of nightmare is a different word, an obsolete one referring to an evil spirit that was once thought to produce feelings of suffocation in people while they slept. By the 14th century the mare was also known as nightmare, and by the late 16th century nightmare was also being applied to the feelings of distress caused by the spirit, and then to frightening or unpleasant dreams.
Examples of nightmare in a Sentence
Sean Krofssik, Hartford Courant, 27 May 2025
Watching the men who trusted him to lead them home devoured by monsters or crushed by clashing rocks was not a fairytale, but a nightmare.
—Michael Gfoeller and David H. Rundell, MSNBC Newsweek, 26 May 2025
Remove Stains Normally, grease stains can be a nightmare to remove, and one slip of tomato sauce onto your favorite blouse or ink spill onto the white carpet can be catastrophic.
—Hallie Milstein, Southern Living, 25 May 2025
The Panthers led 1-0 Thursday just 77 seconds into Game 2 in a start straight out of a nightmare for Brind’Amour as Gustav Forsling put in a snap shot that turned Raleigh quiet.
—Greg Cote, Miami Herald, 23 May 2025
See All Example Sentences for nightmare
Cite this Entry
“Nightmare.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nightmare. Accessed 3 Jun. 2025.
Copy CitationKids Definition
nightmare
noun
Middle English nightmare "evil spirit thought to haunt people during sleep," from night "night" and mare "spirit," from Old English mare "evil spirit haunting people in sleep"
Medical Definition
nightmare
noun
Share