kidney
Americannoun
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Anatomy. either of a pair of bean-shaped organs in the back part of the abdominal cavity that form and excrete urine, regulate fluid and electrolyte balance, and act as endocrine glands.
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Zoology. a corresponding organ in other vertebrate animals or an organ of like function in invertebrates.
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the meat of an animal's kidney used as food.
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constitution or temperament.
He was a quiet child, of a different kidney from his boisterous brothers.
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kind, sort, or class.
He is only at ease with men of his own kidney.
noun
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either of two bean-shaped organs at the back of the abdominal cavity in man, one on each side of the spinal column. They maintain water and electrolyte balance and filter waste products from the blood, which are excreted as urine
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the corresponding organ in other animals
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the kidneys of certain animals used as food
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class, type, or disposition (esp in the phrases of the same or a different kidney )
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Either of a pair of organs that are located in the rear of the abdominal cavity in vertebrates. The kidneys regulate fluid balance in the body and filter out wastes from the blood in the form of urine. The functional unit of the kidney is the nephron. Wastes filtered from the blood by the nephrons drain into the ureters, muscular tubes that connect each kidney to the bladder.
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See also nephron
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of kidney
1275–1325; Middle English kidenei, kidenere (singular), kideneres, kideneren (plural); origin uncertain; perhaps a compound based either on nere (singular), neres (plural) kidney ( Old English *nēore; compare Old High German nioro, Old Norse nȳra ); or ei (singular), eiren (plural) egg 1, Old English ǣg (singular), ǣgru (plural) (by association with the organ's shape); for the first element compare dial. kid pod (akin to cod 2 )
Explanation
Most people are born with two kidneys, internal organs with the job of filtering waste and excreting urine. All vertebrates — animals with spines — have kidneys. Human kidneys are shaped like large beans, and this is where the "kidney bean," a common red-colored bean, gets its name. The organs called kidneys are vital to life, as they filter bad stuff from your blood, help your body get rid of waste, regulate your blood pressure, and even produce hormones. The word kidney is probably a compound of the Old English cwið, "womb," and ey, "egg," describing the organ's shape.
Vocabulary lists containing kidney
Human Anatomy and Physiology - Introductory
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Human Anatomy and Physiology - High School
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Human Anatomy and Physiology - Middle School
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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.
See Examples For:
"A mineral which, taken in excess, can lead to bone marrow and kidney problems," she reads.
From BBC ● Jul. 13, 2026
The 79-year-old former Hall & Oates rocker says he recently underwent a kidney transplant from ‘a very kind and generous living donor.’
From Los Angeles Times ● Jul. 8, 2026
When she wasn’t working, Robertson helped her husband manage complications from juvenile diabetes and a brain tumor — including kidney issues, the loss of vision in one eye and a compromised immune system.
From MarketWatch ● Jul. 7, 2026
Unlike other life-threatening diseases, like kidney failure or heart failure, dementia causes people to lose the ability to direct their own care fairly far in advance of their death, Gaster says.
From The Wall Street Journal ● Jul. 3, 2026
Mrs. Flores had selected two cans of kidney beans and put them on the counter.
From "145th Street: Short Stories" by Walter Dean Myers
Lungs, heart, kidneys, liver, brain, testicles, the fluid in our eyes, and ovaries—all have microplastics, says Stapleton.
From The Wall Street Journal ● Jul. 17, 2026
With rhabdomyolysis, kidneys become strained when proteins and electrolytes from damaged muscle tissue are released into the bloodstream.
From Los Angeles Times ● Jul. 8, 2026
This rare condition, which mostly impacts children, occurs when bacterial toxins spread throughout the body and damage red blood cells, causing clots in the organs, primarily the kidneys.
From Salon ● Jun. 22, 2026
This growing body of evidence suggests that managing diabetes protects more than the heart and kidneys, it also helps preserve brain function.
From Science Daily ● Jun. 17, 2026
It produces degenerative changes in the liver and kidneys.
From "Silent Spring" by Rachel Carson
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.
