Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

nightmare

play
noun night·mare \ˈnīt-ˌmer\

Simple Definition of nightmare

  • : a dream that frightens a sleeping person : a very bad dream

  • : a very bad or frightening experience or situation

Source: Merriam-Webster's Learner's Dictionary

Full Definition of nightmare

  1. 1 :  an evil spirit formerly thought to oppress people during sleep

  2. 2 :  a frightening dream that usually awakens the sleeper

  3. 3 :  something (as an experience, situation, or object) having the monstrous character of a nightmare or producing a feeling of anxiety or terror

nightmare adjective
nightmarish play \-ˌmer-ish\ adjective
nightmarishly adverb

Examples of nightmare in a sentence

  1. Mommy, I had a really scary nightmare.

  2. 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 of nightmare

Middle English, from 1night + 1mare


First Known Use: 14th century



NIGHTMARE Defined for Kids

nightmare

play
noun night·mare \ˈnīt-ˌmer\

Definition of nightmare for Students

  1. 1 :  a frightening dream

  2. 2 :  a horrible experience

nightmarish \ˈnīt-ˌmer-ish\ adjective


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 Dictionary

nightmare

play
noun night·mare \ˈnīt-ˌma(ə)r, -ˌme(ə)r\

Medical Definition of nightmare

  1. :  a frightening or distressing dream that usually awakens the sleeper





Seen and Heard

What made you want to look up nightmare? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a smart aleck

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image567572573

Which of these is a synonym of unctuous?

angry oily prompt maudlin
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ