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 Just about everybody in the Rex Theater knew that the death of Beau Biden in 2015 from a malignant brain tumor had prevented his grieving father from running for the Democratic presidential nomination in 2016. Susan Page, USA TODAY, "Analysis: Joe Biden insists he still has a path to the nomination. Others have trouble seeing it.," 12 Feb. 2020 Carter was born cancer-free, but at 6 months old, two tumors were discovered in his eyes. Mallory Hughes, CNN, "Three young brothers are fighting the same rare childhood cancer," 11 Feb. 2020 The drug aims to stop the growth and division of cancer cells, which can prevent tumors from growing, potentially shrinking them. Dallas News, "Motley Fool: Are you ready for retirement, plus this week’s trivia," 9 Feb. 2020 Researchers say the results, released on Wednesday in six papers in Nature and 17 in other journals, could pave the way for full genome sequencing of all patients’ tumors. Rodrigo Pérez Ortega, Science | AAAS, "Top stories: Faster ocean currents, coronavirus DNA, and the largest-ever study of cancer genomes," 7 Feb. 2020 The book explores Albom's fatherly relationship with Chika Jeune, a Haitian orphan who traveled the globe with him in search of a cure for an incurable brain tumor. Chris Thomas, Detroit Free Press, "Mitch Albom's 'Finding Chika' book tour postponed in Philippines amid coronavirus outbreak," 7 Feb. 2020 Solomon spent the next month under the study of ultrasound technicians and surgical oncologists, who found an oblong tumor stuck to his sciatic nerve. Eren Orbey, The New Yorker, "The Visceral Satisfactions of a Disabled Photographer’s Gaze," 6 Feb. 2020 Koch played an integral role in the Microgravity Crystals investigation, which aims to freeze proteins associated with tumor growth. Jennifer Leman, Popular Mechanics, "Astronaut Christina Koch Returns Home from a Groundbreaking Year in Space," 6 Feb. 2020 The majority of those waiting to leave are women and children who have brain tumors or aggressive forms of cancer, or who need organ transplants or reconstructive surgery, the World Health Organization said. Declan Walsh, BostonGlobe.com, "Mercy flight leaves Yemen capital, cracking a 3-year blockade," 3 Feb. 2020

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

15 Feb 2020

Cite this Entry

“Tumor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tumor. Accessed 27 Feb. 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

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