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

Activity can help doctors distinguish between a rapidly growing tumor and a benign mass of cells. Julie Grisham, Scientific American, "Faster, clearer PET images offer new views on disease," 9 July 2019 So far the museum has completed dozens of labels for its extensive collection, which includes sections of brains, hearts, tumors and other biological remains. Jennifer Nalewicki, Smithsonian, "How One Museum Is Giving a Voice to Former Mental Health Patients," 2 July 2019 Kura is testing the drug for several forms of blood cancer, as well as solid tumors. San Diego Union-Tribune, "Kura Oncology reports lymphoma success with cancer drug," 17 June 2019 Studies are testing algorithms to read x-rays, detect brain bleeds, pinpoint tumors, and more. Jennifer Couzin-frankel, Science | AAAS, "Artificial intelligence could revolutionize medical care. But don’t trust it to read your x-ray just yet," 17 June 2019 The plan was to shrink the tumor and then have a second surgery to remove it and a portion of the pancreas. Joyce Rudolph, latimes.com, "Community: Longtime columnist goes through fight of her life," 3 June 2019 The simulation looks at how gold nanoparticles in a virtual breast tumor are heated by exposure to near-infrared light. Fox News, "Techniques developed by astronomers to understand space could help fight against breast cancer," 3 July 2019 Unfortunately, scans have revealed some new tumors, but John said that wasn't totally unexpected. Jim Ayello, Indianapolis Star, "In fight for his life, John Andretti won't quit helping kids with Race for Riley," 27 June 2019 The other drug, MRTX849, is in early testing in people with advanced solid tumors that have a mutation in a gene called KRAS G12C. More information on the drugs can be found at clinicaltrials.gov by searching for their names. San Diego Union-Tribune, "Cancer drug developer Mirati Therapeutics raising nearly $204 million," 25 June 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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Statistics for tumor

Last Updated

19 Jul 2019

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Time Traveler for tumor

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

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More Definitions for tumor



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

Rhyming Dictionary: Words that rhyme with tumor

Thesaurus: All synonyms and antonyms for 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

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