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:
I had had a kidney transplant from Phillip Palmer, who’s the morning anchor at ABC7, and it was a really big story back in 2007.
From Los Angeles Times ● Oct. 1, 2026
When he got to the hospital in Nottinghamshire, Patrick said his mother was "totally unconscious", suffering continuous fits and going into kidney failure.
From BBC ● Oct. 1, 2026
"I would wake up in the night vomiting and I was always worried that maybe my appendix had burst or I had a kidney infection or something like that," she recalled.
From BBC ● Sep. 30, 2026
The data pointed to the drug’s potential to reduce the so-called urine protein-to-creatinine ratio, which is associated with the preservation of long-term kidney function, Roche said.
From The Wall Street Journal ● Sep. 23, 2026
I was still fishing and wondering if I could pull my liver up, or my kidney, or some organ we had studied in science when suddenly Mrs. Maxy swooped down on me.
From "Joey Pigza Swallowed the Key" by Jack Gantos
The teenager donated her kidneys, liver, pancreas, eyes and tissue, saving the lives of four people and giving sight to two more, her family said.
From BBC ● Sep. 22, 2026
Our kidneys can handle a lot of fluid.
From The Wall Street Journal ● Aug. 27, 2026
After they are formed, these molecules can be absorbed into the body and carried to different organs, particularly the liver and kidneys.
From Science Daily ● Aug. 24, 2026
Creatine is a natural compound in the body produced in the kidneys, liver and pancreas.
From BBC ● Aug. 20, 2026
But only red blood cells were affected by the altered genes—not Noel’s neurons or kidneys or liver cells or muscle cells.
From "The Gene" by Siddhartha Mukherjee
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.
