tu·​mor | \ ˈtü-mər How to pronounce tumor (audio) , ˈtyü- \

Definition of tumor

1 : an abnormal benign or malignant new growth of tissue that possesses no physiological function and arises from uncontrolled usually rapid cellular proliferation

called also neoplasm

2 : a swollen or distended part … houses that bulged with the tumors and warts of … ornamental architecture …— W. A. White

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Other Words from tumor

tumoral \ ˈtü-​mə-​rəl How to pronounce tumoral (audio) , ˈtyü-​ \ adjective
tumorlike \ ˈtü-​mər-​ˌlīk How to pronounce tumorlike (audio) , ˈtyü-​ \ adjective

Examples of tumor in a Sentence

the scan showed a small tumor in her abdomen
Recent Examples on the Web His daughter, Sara Lynn Black, said the cause was a brain tumor. Katie Hafner, New York Times, "Peter Kirstein, Father of the European Internet, Is Dead at 86," 8 Jan. 2020 Mexico’s ambassador to Argentina who was caught on camera trying to steal a book from a bookstore in October has resigned, blaming yearslong health problems that stemmed from a brain tumor, officials said. Fox News, "Mexico’s ambassador to Argentina resigns after being caught shoplifting," 24 Dec. 2019 After noting that one individual had a large bone tumor, Pettigrew began to see how a mummy was a record of a real person. National Geographic, "Europe's morbid 'mummy craze' has been an obsession for centuries," 10 Dec. 2019 Another begins with the discovery of a toilet cam mounted in a public restroom; the episode goes on to deal with pedophilia—and the discovery that the pedophile in question had a brain tumor that, her lawyer argued, was causing her behavior. Megan Garber, The Atlantic, "Olivia Ex Machina," 2 Dec. 2019 In any case, there are millions of Americans with this OCD behavior who, of course, do not have a brain tumor. Annie Lane | Creators.com, oregonlive, "Dear Annie: If you’re invited to a holiday dinner, don’t just sit there afterward," 23 Nov. 2019 Henry had a brain tumor next to his brain stem, on his posterior fossa. The New Yorker, "Rob Delaney on Writing While Grieving and the Real Work of Comedy," 20 Oct. 2019 Robert had a life-threatening tumor on the top of his spine. Ada Tseng, Daily Pilot, "Through Westminster Arts Academy, the Rios siblings honor the legacy of their larger-than-life father," 25 Sep. 2019 As Webb was graduating from high school, barely two years later, his mother suddenly died, aged only thirty-six, of complications resulting from an inoperable brain tumor. Longreads, "The Story of Country Music’s Great Songwriting Duo," 3 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'tumor.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of tumor

15th century, in the meaning defined at sense 2

History and Etymology for tumor

Middle English tumour, from Latin tumor, from tumēre

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Time Traveler for tumor

Time Traveler

The first known use of tumor was in the 15th century

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Statistics for tumor

Last Updated

18 Jan 2020

Cite this Entry

“Tumor.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/tumor. Accessed 29 January 2020.

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More Definitions for tumor


How to pronounce tumor (audio)

English Language Learners Definition of tumor

: a mass of tissue found in or on the body that is made up of abnormal cells


tu·​mor | \ ˈtü-mər How to pronounce tumor (audio) , ˈtyü- \

Kids Definition of tumor

: an abnormal growth of body tissue


variants: or chiefly British tumour \ ˈt(y)ü-​mər How to pronounce tumour (audio) \

Medical Definition of tumor

: an abnormal benign or malignant new growth of tissue that possesses no physiological function and arises from uncontrolled usually rapid cellular proliferation — see cancer sense 1, carcinoma, sarcoma

Other Words from tumor

tumorlike \ -​ˌlīk How to pronounce tumorlike (audio) \ adjective

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More from Merriam-Webster on tumor

Thesaurus: All synonyms and antonyms for tumor

Rhyming Dictionary: Words that rhyme with tumor

Spanish Central: Translation of tumor

Nglish: Translation of tumor for Spanish Speakers

Britannica English: Translation of tumor for Arabic Speakers

Britannica.com: Encyclopedia article about tumor

Comments on tumor

What made you want to look up tumor? Please tell us where you read or heard it (including the quote, if possible).


to assert without proof or before proving

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