tumor

American  

[too-mer, tyoo-] / ˈtu mər, ˈtyu- /

especially British, tumour

noun

1. a swollen part; swelling; protuberance.

2. an uncontrolled, abnormal, circumscribed growth of cells in any animal or plant tissue; neoplasm.

3. Archaic.

   1. inflated pride; haughtiness.

   2. pompous language; bombast.

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tumor Scientific  

/ to̅o̅′mər /

1. See neoplasm See Note at cancer

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tumor Cultural  

1. An abnormal mass of new tissue growth that serves no function in the body. Tumors are usually classified as benign or malignant and are often caused by cancer.

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Other Word Forms

• antitumor adjective
• antitumoral adjective
• nontumorous adjective
• tumoral adjective
• tumorlike adjective
• tumorous adjective

Etymology

Origin of tumor

First recorded in 1535–45; from Latin: “a swelling, swollen state,” equivalent to tum(ēre) “to swell” + -or noun suffix ( -or ¹ )

Example Sentences

Removal of the tumor was scheduled for two months later, so Duong went home to his family for the weekend.

From Los Angeles Times • Mar. 30, 2026

In real patients, drugs are delivered through the bloodstream, and tumor blood vessels are often disorganized, which may further contribute to uneven drug distribution.

From Science Daily • Mar. 27, 2026

As a result, the conditions become more favorable for tumor growth and tumour metastasis.

From Science Daily • Mar. 25, 2026

MangroveGS can work directly with tumor samples collected in hospitals.

From Science Daily • Mar. 21, 2026

Within two weeks, some of the nodules had grown to two centimeters —about the size of Henrietta’s tumor when she went in for her radium treatments.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot

Related Words

• Cancer
• carcinoma
• cyst
• lump
• swelling