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dialysis

American  
[dahy-al-uh-sis] / daɪˈæl ə sɪs /

noun

dialyses plural
  1. Physical Chemistry. the separation of crystalloids from colloids in a solution by diffusion through a membrane.

  2. 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.

  3. Medicine/Medical. (in kidney disease) the process by which uric acid and urea are removed from circulating blood by means of a dialyzer.


dialysis British  
/ daɪˈælɪsɪs, ˌdaɪəˈlɪtɪk /

noun

  1. 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

  2. med See haemodialysis peritoneal dialysis

"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

dialysis Scientific  
/ dī-ălĭ-sĭs /
  1. 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.

  2. 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.


dialysis Cultural  
  1. The separation of large molecules from small molecules by passage through a membrane.


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

Derived Forms

Inflected Forms

noun

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.

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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.

"We were on cloud nine... it was just the happiest day ever going," the renal dialysis nurse who lives in Dumfries said.

From BBC • Jun. 5, 2026

The child, the complaint says, required dialysis and blood transfusions and suffered seizures and decreased pancreatic function.

From Los Angeles Times • May 31, 2026

Chronic kidney disease is no longer seen only as a late-stage condition that leads to dialysis or transplant.

From Science Daily • May 29, 2026

There is no treatment; doctors can offer only supportive care, such as hydration, artificial respiration or dialysis.

From Salon • May 9, 2026

No time for jokes, and no time for tears, because Ma had to get to dialysis, and we had to make sure we got to the hospital before Momly went into surgery.

From "Patina" by Jason Reynolds

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