dialysis
Americannoun
plural
dialyses-
Physical Chemistry. the separation of crystalloids from colloids in a solution by diffusion through a membrane.
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Biochemistry. the separation of large molecules, as proteins, from small molecules and ions in a solution by allowing the latter to pass through a semipermeable membrane.
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Medicine/Medical. (in kidney disease) the process by which uric acid and urea are removed from circulating blood by means of a dialyzer.
noun
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the separation of small molecules from large molecules and colloids in a solution by the selective diffusion of the small molecules through a semipermeable membrane
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med See haemodialysis peritoneal dialysis
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The separation of the smaller molecules in a solution from the larger molecules by passing the solution through a membrane that does not allow the large molecules to pass through.
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A medical procedure in which this technique of molecular separation is used to remove metabolic waste products or toxic substances from the blood. Dialysis is required for individuals with severe kidney failure.
Discover More
A common treatment for kidney disease is the use of a dialysis machine to filter toxic substances from the blood, a function that the kidneys normally perform.
Other Word Forms
Etymology
Origin of dialysis
First recorded in 1580–90; from Late Latin, from Greek diálysis “separation”; equivalent to dia- + -lysis
Explanation
Dialysis is a crucial medical procedure that functions as an artificial kidney, filtering and cleaning the blood for patients with kidney failure. It also describes a process that separates small particles from large particles in a liquid by using a special membrane. Dialysis has two key meanings. Medically, it’s a life-saving treatment for people whose kidneys can't properly filter their blood: Dialysis uses either a machine or the lining of the abdomen to remove waste and excess fluids. Scientifically, dialysis involves separating different substances in a solution by allowing them to diffuse through semipermeable membranes at varying rates. Dialysis is essential in both healthcare and scientific fields.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
There is no treatment; doctors can offer only supportive care, such as hydration, artificial respiration or dialysis.
From Salon • May 9, 2026
The kidney dialysis company topped first-quarter earnings and revenue estimates while also hiking full-year guidance.
From Barron's • May 6, 2026
The German dialysis specialist said U.S. treatment volumes declined and reported a lower net profit due to restructuring costs.
From The Wall Street Journal • May 6, 2026
"Life on dialysis is horrendous and so I wanted to help."
From BBC • Mar. 16, 2026
When he asked for more information about his prognosis, the doctor told him that unless dialysis treatment began immediately, he probably didn’t have more than three months to live.
From "Endgame" by Frank Brady
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.