Simple Definition of nightmare
: a dream that frightens a sleeping person : a very bad dream
: a very bad or frightening experience or situation
Full Definition of nightmare
1 : an evil spirit formerly thought to oppress people during sleep
2 : a frightening dream that usually awakens the sleeper
3 : something (as an experience, situation, or object) having the monstrous character of a nightmare or producing a feeling of anxiety or terror
nightmarishplay \-ˌmer-ish\ adjective
Examples of nightmare in a sentence
Mommy, I had a really scary nightmare.
The party was a complete nightmare.
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 a 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.
Origin and Etymology of nightmare
Middle English, from 1night + 1mare
First Known Use: 14th century
NIGHTMARE Defined for Kids
Definition of nightmare for Students
1 : a frightening dream
2 : a horrible experience
History for nightmare
The -mare in nightmare comes from an Old English word for a kind of evil spirit. Such spirits were believed to bother people who were sleeping.
Medical Definition of nightmare
: a frightening or distressing dream that usually awakens the sleeper
Seen and Heard
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