nightmare

Etymology

Recorded from c. 1300,^[1] compounded from night + mare “goblin that causes nightmares, incubus”.^[1][2] It originally meant an evil female spirit thought to afflict sleepers with a feeling of suffocation;^[1][3] in the mid-16th century the sense shifted to the sensation itself,^[1] to “any bad dream” by 1829, and to “very distressing experience” by 1831.^[1]

Cognate with Middle Dutch nachtmare and German Nachtmahr.^[2][1]

References

1. [1] [2] [3] [4] [5] [6] Harper, Douglas, Online Etymology Dictionary, https://www.etymonline.com
2. [1] [2] Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
3. [1] The American Heritage Dictionary of the English Language, Boston: Houghton Mifflin