[ toh-nuh s ]
/ ˈtoʊ nəs /

noun Physiology.

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. 2019

Examples from the Web for 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.

    Instinct|George Oliver Smith
  • The tonus of the muscles at the moment of examination may create differences inappreciable during relaxation.

British Dictionary definitions for tonus


/ (ˈtəʊnəs) /


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

Medicine definitions for tonus


[ tōnəs ]


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.