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[som-nam-byuh-liz-uh m, suh m-] /sɒmˈnæm byəˌlɪz əm, səm-/
1790-1800; < New Latin somnambulismus, equivalent to somn(us) sleep + ambul(āre) to walk + -ismus -ism
Related forms
somnambulist, noun
somnambulistic, adjective
semisomnambulistic, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for somnambulism
  • Describes therapy program for treating somnambulism.
British Dictionary definitions for somnambulism


a condition that is characterized by walking while asleep or in a hypnotic trance Also called noctambulism
Derived Forms
somnambulist, noun
somnambulistic, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for somnambulism

1786, "walking in one's sleep or under hypnosis," from French somnambulisme, from Modern Latin somnambulus "sleepwalker," from Latin somnus "sleep" (see Somnus) + ambulare "to walk" (see amble (v.)).

Originally brought into use during the excitement over "animal magnetism;" it won out over noctambulation. A stack of related words came into use early 19c., e.g. somnambule "sleepwalker" (1837, from French somnambule, 1690s), earlier somnambulator (1803); as adjectives, somnambulary (1827), somnambular (1820).

Online Etymology Dictionary, © 2010 Douglas Harper
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somnambulism in Medicine

somnambulism som·nam·bu·lism (sŏm-nām'byə-lĭz'əm)
See sleepwalking.

som·nam'bu·lis'tic adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Article for somnambulism


a behavioral disorder of sleep in which a person sits up and performs various motor actions, such as standing, walking about, talking, eating, screaming, dressing, going to the bathroom, or even leaving the house. The episode usually ends with the sleepwalker returning to sleep, with no subsequent memory of the episode. Sleepwalking is most common in children, though it may also appear in adolescents and young adults. It occurs only during deep sleep, when dreams are basically absent. Sleepwalking becomes dangerous only when the possibility exists of the sleepwalker accidentally injuring himself.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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