kidney
Americannoun
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kidneys
plural
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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:
In severe cases, mycotoxin exposure has been associated with liver and kidney damage, suppression of the immune system, and cancer.
From Science Daily ● Aug. 28, 2026
In May 2026, she postponed an upcoming Las Vegas residency because of treatment for kidney stones, saying it would take some time to heal and be "stage-performance ready".
From BBC ● Aug. 25, 2026
In September 2025, she missed the announcement of a Dollywood attraction to recover from a kidney stone.
From Los Angeles Times ● Aug. 25, 2026
E. coli can cause stomach cramps, diarrhea and vomiting, and can lead to serious kidney problems that require hospitalization, according to public-health officials.
From The Wall Street Journal ● Aug. 21, 2026
Ron had a piece of steak and kidney pie halfway to his mouth, but he’d forgotten all about it.
From "Harry Potter and the Sorcerer's Stone" by J.K. Rowling
Creatine is a natural compound in the body produced in the kidneys, liver and pancreas.
From BBC ● Aug. 20, 2026
In DKD, the kidneys are already dealing with elevated pressure and hyperfiltration, a condition in which their filtering structures are placed under excessive strain.
From Science Daily ● Aug. 18, 2026
According to the outlet, Collins has permanent scarring on his pancreas, and his kidneys “barely” function.
From Los Angeles Times ● Aug. 3, 2026
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
For the first time since I read his file I wondered if you could actually die from having bad kidneys.
From "We Were Here" by Matt De La Peña
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.
