tu·​mor | \ˈtü-mər, 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 , ˈtyü-​ \ adjective
tumorlike \ ˈtü-​mər-​ˌlīk , ˈtyü-​ \ adjective

Examples of tumor in a Sentence

the scan showed a small tumor in her abdomen

Recent Examples on the Web

In April 2017, Maria Menounos' life changed forever after the unthinkable happened — an MRI revealed a benign brain tumor diagnosed as meningioma. Kara Ladd, Redbook, "5 Wellness Tips Maria Menounos Learned After a Terrifying Diagnosis," 21 June 2018 Chika's Story documents Free Press columnist Mitch Albom and his wife's two-year, heartbreaking journey to try to save the life of an orphaned Haitian girl diagnosed with Diffuse Intrinsic Pontine Glioma (DIPG), a rare and always fatal brain tumor. Steven Pepple, Detroit Free Press, "Free Press wins Emmys for 12th and Clairmount, 4 other documentaries," 17 June 2018 Complicating matters even further, an MRI then turned up a benign tumor unrelated to the cancer. Billboard Staff, Billboard, "Interscope CEO John Janick Reveals Cancer Battle," 14 June 2018 Recovery time can correspond to how serious the issue is, with most doctors citing one day needed to recover in the case of a benign tumor or cyst. Kenzie Bryant, Vanities, "A Complete Timeline of Melania Trump’s 24 Days Out of the Public Eye," 4 June 2018 By the time that new tumor has grown large enough to show up on a CT scan, the cancer is likely incurable. Delia O'hara, Discover Magazine, "A Blood Test to Root Out Cancer," 18 May 2018 Brown is being treated for a brain tumor at Johns Hopkins Hospital. Jon Meoli, baltimoresun.com, "Orioles notes: O'Day surgery fixes hamstring with eye toward 2019; Tillman schedule unclear," 1 July 2018 These are, at present, completely unproven therapies for solid tumors. Maggie Fox /, NBC News, "Is chemo obsolete? Not by a long shot, cancer experts say," 24 June 2018 Loaded: 0% Progress: 0% 0:00 / 1:37 Sager night Advertisement Colleyville Heritage set up donation tables at Tuesday night's baseball game vs. Grapevine for girls basketball coach Dianna Sager, who underwent surgery for a brain tumor on April 16. Drew Davison, star-telegram, "From Mansfield Timberview to the Harlem Globetrotters? Meet Lili Thompson," 19 June 2018

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

8 Nov 2018

Look-up Popularity

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, ˈtyü-\

Kids Definition of tumor

: an abnormal growth of body tissue


variants: or chiefly British tumour \ ˈt(y)ü-​mər \

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 \ adjective

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Comments on tumor

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to express warning or disapproval

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