1. Physiology. (of tissue) having less than the normal tone.
  2. Physical Chemistry. noting a solution of lower osmotic pressure than another solution with which it is compared (opposed to hypertonic).Compare isotonic(def 1).

Origin of hypotonic

First recorded in 1890–95; hypo- + tonic
Related formshy·po·to·nic·i·ty [hahy-poh-toh-nis-i-tee] /ˌhaɪ poʊ toʊˈnɪs ɪ ti/, noun
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British Dictionary definitions for hypotonicity


  1. pathol (of muscles) lacking normal tone or tension
  2. (of a solution) having a lower osmotic pressure than that of a specified, generally physiological, solutionCompare hypertonic, isotonic
Derived Formshypotonicity (ˌhaɪpətəˈnɪsɪtɪ), noun
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 hypotonicity



1873, from hypo- + tonic.

Online Etymology Dictionary, © 2010 Douglas Harper

hypotonicity in Medicine


  1. Having less than normal tone or tension, as of muscles or arteries.
  2. Having a lower osmotic pressure than a reference solution.
Related formshy′po•to•nici•ty (-tə-nĭsĭ-tē) n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.