sleepy; drowsy.
tending to cause sleep.

Origin of somnolent

1425–75; late Middle English sompnolent < Old French < Latin somnolentus, derivative of somnus sleep; see -ulent
Related formssom·no·lence, som·no·len·cy, nounsom·no·lent·ly, adverbhy·per·som·no·lence, nounhy·per·som·no·lent, adjectivehy·per·som·no·lent·ly, adverbsem·i·som·no·lence, nounsem·i·som·no·lent, adjectivesem·i·som·no·lent·ly, adverbun·som·no·lent, adjectiveun·som·no·lent·ly, adverb

Synonyms for somnolent Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for somnolence

Historical Examples of somnolence

  • They pretended they desired this tranquillity, and somnolence of their hearts.

    Therese Raquin

    Emile Zola

  • A crack on the head makes you dizzy and into her dizziness a somnolence had entered.

    The Paliser case

    Edgar Saltus

  • There could be no doubt of Tim's somnolence for he gave unmistakable evidence of it.

    Adrift in the Wilds

    Edward S. Ellis

  • He broke into camp and roused McHale from a state of somnolence and tobacco.

    Desert Conquest

    A. M. Chisholm

  • Somnolence is nothing more than an inordinate tendency to sleep.

    Sleep and Its Derangements

    William A. Hammond

British Dictionary definitions for somnolence



drowsy; sleepy
causing drowsiness
Derived Formssomnolence or somnolency, nounsomnolently, adverb

Word Origin for somnolent

C15: from Latin somnus sleep
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for somnolence

late 14c., from Old French sompnolence (14c.), from Latin somnolentia "sleepiness," from somnolentus, from somnus "sleep" (see somnus). Related: Somnolency.



mid-15c., sompnolent, from Old French sompnolent (Modern French somnolent) or directly from Latin somnolentus "sleepy, drowsy," from somnus "sleep" (see Somnus). Respelled 17c. on Latin model.

Online Etymology Dictionary, © 2010 Douglas Harper

somnolence in Medicine




A state of drowsiness; sleepiness.
A condition of semiconsciousness approaching coma.




Drowsy; sleepy.
Inducing or tending to induce sleep; soporific.
In a condition of incomplete sleep; semicomatose.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.