nightmare
Americannoun
-
nightmares
plural
-
a terrifying dream in which the dreamer experiences feelings of helplessness, extreme anxiety, sorrow, etc.
- Synonyms:
- phantasmagoria
-
a condition, thought, or experience suggestive of a nightmare.
the nightmare of his years in prison.
-
(formerly) a monster or evil spirit believed to oppress persons during sleep.
noun
-
a terrifying or deeply distressing dream
-
-
an event or condition resembling a terrifying dream
the nightmare of shipwreck
-
( as modifier )
a nightmare drive
-
-
a thing that is feared
-
(formerly) an evil spirit supposed to harass or suffocate sleeping people
Usage
Where does the word nightmare come from? Nightmares are scary and unpleasant. But you can rest easy knowing that the fascinating origin of the word nightmare makes it clear humans have been having them for hundreds of years. In Old English, a mare was a kind of evil or cursed spirit. Mares appear in all kinds of folklore, including German and Slavic stories. Mares were said to ride on people's chests at night, causing suffocation and bad dreams. These mares, often female, were known as nightmares (because they came at night). By the 16th century, the word nightmare came to refer to a sensation of suffocation or anxiety during sleep, and now simply a bad dream. While nightmares are terrifying, there is good news: at least most of us don't worry about evil spirits trying to suffocate us in our sleep anymore. The roots of these other words may get a rise—of laughter or surprise—out of you. Run on over to our roundup of them at "Weird Word Origins That Will Make Your Family Laugh."
Synonym Usage
See dream.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of nightmare
Middle English word dating back to 1250–1300; see origin at night, mare 2
Explanation
If you wake with a start after a terrifying dream, you've had a nightmare. A nightmare is not just a bad dream — it's seriously scary or upsetting. You can also use nightmare to describe something terrible that happens during the day. Your run-in with a skunk in your back yard might be a nightmare, for example, or your humiliating experience forgetting your lines in a play. In the late thirteenth century, a nightmare was "an evil female spirit afflicting sleepers with a feeling of suffocation," from the Old English word mare, "incubus or goblin."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
It frequently plays like a fun house nightmare version of “Our Town.”
From Los Angeles Times ● Oct. 16, 2026
That ability to send pitchers plummeting into a nightmare was on full display in Monday’s 7-4 win over the Dodgers.
From The Wall Street Journal ● Oct. 13, 2026
Several fear this Christmas will be a "nightmare".
From BBC ● Oct. 13, 2026
Cheryl Creasey said trying to sell her home in Everett, Wash., has been a nightmare.
From The Wall Street Journal ● Oct. 13, 2026
Mary Todd Lincoln burst into the room, and the bright gaslight confirmed to her that this was not a nightmare as she hoped it was—this was real.
From "Chasing Lincoln's Killer" by James L. Swanson
For days he suffered nightmares as he struggled to understand how he got hacked.
From The Wall Street Journal ● Oct. 11, 2026
So the news "was like her nightmares have come true," said the man.
From Barron's ● Sep. 27, 2026
She said she had nightmares every night and didn’t think she’d feel safe in Berkeley again.
From Los Angeles Times ● Sep. 23, 2026
Her sister wrote her a letter explaining why she could not come to their wedding, describing "terrible nightmares" and the worry that she would never see her again.
From BBC ● Sep. 10, 2026
It was hard to remember that this was the Palace of Illusions and not of, say, nightmares.
From "Aru Shah and the End of Time" by Roshani Chokshi
Random Word
Spin the wheel and learn a new word!
Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
