tumor

noun

tu·​mor ˈtü-mər 

ˈtyü-

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 

ˈtyü-

adjective

tumorlike

ˈtü-mər-ˌlīk 

ˈtyü-

adjective

Synonyms of tumor

• lump
• neoplasm
• cyst
• growth
• carcinoma

Examples of tumor in a Sentence

the scan showed a small tumor in her abdomen

Recent Examples on the Web

The researchers used the approach to design proteins that bind tightly to fibroblast activation protein alpha (FAP), a molecule associated with solid tumors. — Neetika Walter, Interesting Engineering, 16 Oct. 2026

But some experts are inferring that the cancer was likely caught early, noting that surgery is often prescribed when the entire tumor can be removed. — Meghana Keshavan, STAT, 16 Oct. 2026

The former University of Virginia standout was reportedly diagnosed with the Grade 4 cancer last year and briefly went into remission, but the tumors returned in July, according to Houston news site Chron. — Tracy Brown, Los Angeles Times, 16 Oct. 2026

Salvador remembers a man in his 30s who had consistent nosebleeds for about six months before an examination revealed a tumor inside his nose. — Angela Haupt, Time, 16 Oct. 2026

Word History

Etymology

Middle English tumour, from Latin tumor, from tumēre

First Known Use

15th century, in the meaning defined at sense 2

Phrases Containing tumor

• anti-tumor
• tumor load
• tumor necrosis factor
• tumor suppressor gene

Rhymes for tumor

• boomer
• humor
• humour
• plumer
• rumor
• rumour
• tumour
• antitumor
• pseudotumor
• consumer
• perfumer

Kids Definition

tumor

noun

tu·​mor ˈt(y)ü-mər 

: 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 

: 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 

adjective