1. having the same osmotic pressure
  2. Having the same concentration of solutes as human blood.
    Use an isotonic saline solution in your neti pot to prevent irritation of your nasal passages.
  3. having equal tension
  4. Of or involving muscular contraction against resistance in which the length of the muscle changes. Antonym is isometric. Isotonic movements are either concentric (working muscle shortens) or eccentric (working muscle lengthens). See also

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