noun
nightmare
NYT-meh-uh
noun
1
A frightening or unpleasant dream.
"She woke up gasping from a nightmare."
2
Any deeply unpleasant, stressful, or frightening situation.
"The flight delay turned our trip home into a total nightmare."
How to Use Nightmare
Learner’s notesIn plain EnglishA scary dream, or by extension any awful, stressful experience.
Common mistake
The "mare" in nightmare has nothing to do with horses — it comes from an old word for a demon.
Common pairings
have a nightmare
a recurring nightmare
a logistical nightmare
Word Forms
nightmared past tense, nightmares plural, nightmares singular
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She woke up gasping from a _____.
Etymology
From Middle English nightmare, from night plus mare, an old word for an evil spirit believed to sit on a sleeper's chest and cause suffocating dreams — not related to the horse sense of "mare."