Meaning & use
isotonic
Last updated
Meanings
adjectivenot comparablebiologymedical
Having the same concentration of dissolved particles as another solution, such as body fluid, so that no net movement of water occurs across a membrane.
Grammar: Often followed by to or with: isotonic to blood. A solution is either isotonic or not.
Patterns
- isotonic to something
- isotonic with something
Saline solution for the drip must be isotonic to blood.
Red blood cells keep their shape in an isotonic solution.
The contact lens fluid is isotonic with tears.
adjectivenot comparabletechnical
Describing a muscle contraction in which the muscle changes length while the load it moves stays constant.
Grammar: Contrasts with isometric, where the muscle stays the same length.
Patterns
- isotonic exercise
- isotonic contraction
Lifting a dumbbell is an isotonic exercise.
The physiotherapist explained isotonic contraction to her patient.
adjectivenot comparableinformal
Describing a sports drink with a similar concentration of sugar and salt to body fluids, designed to be absorbed quickly.
Grammar: Used before a noun: an isotonic drink.
Patterns
- isotonic drink
Runners often sip an isotonic drink during a marathon.
The isotonic sports drink replaced her lost salts.
Common combinations
- isotonic solution
- The nurse prepared an isotonic solution of salt water.
- isotonic drink
- He grabbed an isotonic drink after the match.
- isotonic exercise
- Cycling and swimming are isotonic exercises.
- isotonic saline
- Isotonic saline is used to rinse wounds.
Synonyms and how they differ
- iso-osmotic
- Iso-osmotic is a more technical term for equal osmotic pressure and is used mainly in laboratories.
Opposites
Word family
Commonly confused: isotonic or isometric? isotonic or isotropic?
isotonic vs isometric
Isometric means a muscle stays the same length while tensing, as in a plank. Isotonic means it changes length, as in a curl.
isotonic vs isotropic
Isotropic means having the same properties in every direction, a different physics term.
Practice
A saline drip must be isotonic. What does that mean for the fluid?
Choose one answer.
Isotonic means matching concentration of dissolved particles, so cells do not swell or shrink. Much saltier would be hypertonic, and no salt would be hypotonic.
Make it your own
Write a sentence using “isotonic”, then check it and compare it with the examples above.