somni-

Also especially before a vowel, somn-.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for somn-

somni-

before a vowel somn-

combining form
  1. sleepsomniferous

Word Origin for somni-

from Latin somnus
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 somn-

somni-

before vowels somn-, word-forming element meaning "sleep," from comb. form of Latin somnus (see Somnus).

Online Etymology Dictionary, © 2010 Douglas Harper

somn- in Medicine

somni-

pref.
  1. Sleep:somnambulism.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.