[toh-nuh s]
See more synonyms for tonus on
noun Physiology.
  1. a normal state of continuous slight tension in muscle tissue that facilitates its response to stimulation.

Origin of tonus

1875–80; < New Latin, special use of Latin tonus < Greek tónos tone Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for tonus

Historical Examples of tonus

  • This tonus is essential to the maintenance of an equalized circulation.

    Arteriosclerosis and Hypertension:

    Louis Marshall Warfield

  • And, of course, one should feel something if it is no more than the tonus of muscle against the mobile bones.


    George Oliver Smith

  • The tonus of the muscles at the moment of examination may create differences inappreciable during relaxation.

British Dictionary definitions for tonus


  1. physiol the normal tension of a muscle at rest; tone

Word Origin for tonus

C19: from Latin, from Greek tonos tone
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

tonus in Medicine


  1. Body or muscular tone; tonicity.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.