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:
This has damaged cutting-edge facilities like Johns Hopkins, which performs the costliest procedures, such as kidney transplants.
From The Wall Street Journal ● Oct. 30, 2026
Because mutations are common across cancers, investors hope the approach will prove to be a platform that works for many of them, from lung to kidney to bladder.
From The Wall Street Journal ● Oct. 24, 2026
The drug manufacturers MSD and Moderna say the same approach is already being tested against other tumours, including kidney, bladder and lung cancer.
From BBC ● Oct. 23, 2026
In addition to helping control blood sugar and manage weight, GLP-1 medications can reduce the risks of certain cardiovascular and kidney problems.
From Science Daily ● Oct. 15, 2026
On January 6, 1884, Mendel died of kidney failure in Brno, his feet swollen with fluids.
From "The Gene" by Siddhartha Mukherjee
It’s naturally produced in our liver, kidneys and pancreas and comes from the amino acids arginine, glycine and methionine — the “building blocks of protein.”
From Los Angeles Times ● Oct. 19, 2026
In the kidneys, LPC70 appears to suppress signaling changes associated with hypertension.
From Science Daily ● Oct. 18, 2026
He explains that if you eat too much, it has to be excreted by the kidneys and liver which can become overloaded.
From BBC ● Oct. 15, 2026
The investigation also produced an unexpected clue involving the kidneys.
From Science Daily ● Sep. 20, 2026
I had weak kidneys & wet the bed every night.
From "In Cold Blood" by Truman Capote
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