tumor
Americannoun
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a swollen part; swelling; protuberance.
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an uncontrolled, abnormal, circumscribed growth of cells in any animal or plant tissue; neoplasm.
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Archaic.
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inflated pride; haughtiness.
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pompous language; bombast.
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Other Word Forms
Etymology
Origin of tumor
First recorded in 1535–45; from Latin: “a swelling, swollen state,” equivalent to tum(ēre) “to swell” + -or noun suffix ( see -or 1)
Explanation
A tumor is a growth — a mass of tissue — that has no function. Tumors can be harmless (benign) or harmful (malignant), but they are never any fun. When a bunch of cells form a new growth in or on an animal, and those cells have no purpose, the result is a tumor. The word tumor comes directly from Latin word for “swelling.” Tumors can be big or small, harmless or harmful. Benign tumors are not a cause for concern, but a malignant tumor is serious and could be cancerous. A doctor must test a tumor to see which kind it is.
Vocabulary lists containing tumor
"Fine?" Vocabulary from the short story
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Slam!
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Insignificant Events in the Life of a Cactus
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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.
He based the upgrade on an “increasing conviction” in a rising class of cancer medication that simultaneously targets immune evasion and blood supply, two pathways crucial to tumor persistence.
From Barron's • May 27, 2026
I had surgery to remove the tumor and then radiation treatments to make sure it didn’t come back.
From MarketWatch • May 27, 2026
But they went back in to see and it was a cancerous tumor.
From Los Angeles Times • May 27, 2026
New studies suggest that drugs such as Ozempic and Zepbound might slow tumor progression and improve survival rates, though more research is needed to confirm the findings.
From The Wall Street Journal • May 22, 2026
Does Ms. Finn think I have a brain tumor?
From "A Mango-Shaped Space" by Wendy Mass
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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.