See more synonyms for tonicity on
  1. tonic quality or condition.
  2. the state of bodily tone.
  3. Physiology. the normal elastic tension of living muscles, arteries, etc., by which the tone of the system is maintained.

Origin of tonicity

First recorded in 1815–25; tonic + -ity Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for tonicity

Historical Examples of tonicity

British Dictionary definitions for tonicity


  1. the state, condition, or quality of being tonic
  2. physiol another name for tonus
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

tonicity in Medicine


  1. Normal firmness or functional readiness in body tissues or organs.
  2. The sustained partial contraction of resting or relaxed muscles.
  3. The osmotic pressure or tension of a solution, usually relative to that of blood.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.