tumor

noun

tu·​mor ˈtü-mər How to pronounce tumor (audio)
ˈtyü-
Synonyms of tumornext
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
tumoral
ˈtü-mə-rəl How to pronounce tumor (audio)
ˈtyü-
adjective
tumorlike
ˈtü-mər-ˌlīk How to pronounce tumor (audio)
ˈtyü-
adjective

Synonyms of tumor

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Examples of tumor in a Sentence

the scan showed a small tumor in her abdomen
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This could allow scientists to customize the particles with different antigens to target individual patients’ tumors. — Neetika Walter, Interesting Engineering, 31 Oct. 2026 Leo’s participation is complicated by his recent lung cancer diagnosis and surgery to remove a lower lobe of his right lung, which had a malignant tumor on it. — Colleen Kane, Chicago Tribune, 30 Oct. 2026 The request was made just 10 days before Leo underwent surgery to remove a cancerous tumor from his right lung. — Nicole Winfield, Los Angeles Times, 30 Oct. 2026 In 2023, the FDA added more than a dozen peptides, including BPC-157 and TB-500, to its list of substances that should not be compounded due to risks of allergic reactions, kidney damage and tumor growth. — Arkansas Online, 29 Oct. 2026 See All Example Sentences for tumor

Word History

Etymology

Middle English tumour, from Latin tumor, from tumēre

First Known Use

15th century, in the meaning defined at sense 2

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

Phrases Containing tumor

Rhymes for tumor

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Browse Nearby Words

tummy
tumor
tumorigenic
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Cite this Entry

“Tumor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/tumor. Accessed 31 Oct. 2026.

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Kids Definition

tumor

noun
tu·​mor ˈt(y)ü-mər How to pronounce tumor (audio)
: an abnormal mass of tissue that arises from normal tissue cells and serves no useful purpose in the body
tumorous
ˈt(y)üm-(ə-)rəs
adjective

Medical Definition

tumor

noun
tu·​mor
variants or chiefly British tumour
ˈt(y)ü-mər How to pronounce tumor (audio)
: 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
tumorlike
-ˌlīk How to pronounce tumor (audio)
adjective

More from Merriam-Webster on tumor

Britannica.com: Encyclopedia article about tumor

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