1
: the separation of substances in solution by means of their unequal diffusion through semipermeable membranes
especially : such a separation of colloids from soluble substances
2
: the process of removing blood from an artery (as of a patient affected with kidney failure), purifying it by dialysis, adding vital substances, and returning it to a vein

called also hemodialysis

Examples of dialysis in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Treatment for the renal syndrome can include intravenous fluids, tube feeding, medications, blood transfusions and potentially dialysis if patients have severe kidney damage, the Cleveland Clinic said. — Sacbee.com, 4 Nov. 2026 In some cases, temporary dialysis may be needed for kidney failure, or surgery for compartment syndrome. — Tom Gavin, EverydayHealth.com, 4 Nov. 2026 Caring for her aunt, who had uterine cancer and dementia and was on dialysis, Gustin spent hours searching government websites for guidance. — Raginee Sudhir Chaurey, CNN Money, 1 Nov. 2026 The Sudan Doctors Network warned the outages endanger hospitals, dialysis centers and blood banks, and threaten the cold storage needed for medicines and vaccines. — Hamza Fahmy, Los Angeles Times, 1 Nov. 2026 See All Example Sentences for dialysis

Word History

Etymology

New Latin, from Greek, separation, from dialyein to dissolve, from dia- + lyein to loosen — more at lose

First Known Use

1861, in the meaning defined at sense 1

Time Traveler
The first known use of dialysis was in 1861

Browse Nearby Words

Cite this Entry

“Dialysis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dialysis. Accessed 9 Nov. 2026.

Kids Definition

dialysis

noun
1
: the separation of substances in solution by means of their unequal diffusion through membranes with pores of a specified maximum size
especially : such a separation of colloids from dissolved substances
2
: the process of removing blood from an artery (as of a patient with failing kidneys), purifying it by dialysis, and returning it to a vein

Medical Definition

dialysis

noun
1
: the separation of substances in solution by means of their unequal diffusion through semipermeable membranes
especially : such a separation of colloids from soluble substances
2
: either of two medical procedures to remove wastes or toxins from the blood and adjust fluid and electrolyte imbalances by utilizing rates at which substances diffuse through a semipermeable membrane:
a
: the process of removing blood from an artery (as of a kidney patient), purifying it by dialysis, adding vital substances, and returning it to a vein

called also hemodialysis

b
: a procedure performed in the peritoneal cavity in which the peritoneum acts as the semipermeable membrane

called also peritoneal dialysis

More from Merriam-Webster on dialysis

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster