cancer

noun

can·​cer ˈkan(t)-sər How to pronounce cancer (audio)
Synonyms of cancernext
1
Cancer
a
: a northern zodiacal constellation between Gemini and Leo
b(1)
: the fourth sign of the zodiac in astrology see Signs of the Zodiac Table
(2)
: one born under the sign of Cancer
I'm a Taurus, but my best friend is a Cancer.
2
[Latin, crab, cancer]
a
: a malignant tumor of potentially unlimited growth that expands locally by invasion and systemically by metastasis
b
: an abnormal bodily state marked by such tumors
3
: something evil or malignant that spreads destructively
… the cancer of hidden resentment.—Irish Digest
4
a
: an enlarged tumorlike plant growth (such as that of crown gall)
b
: a plant disease marked by such growths
cancerous
ˈkan(t)s-rəs How to pronounce cancer (audio)
ˈkan(t)-sə-
adjective
cancerously adverb

Did you know?

The Latin word cancer, meaning “crab,” was also given as a name to several diseases. One of the diseases was the abnormal, spreading mass of tissue we call a tumor. A possible explanation for this extended use of cancer is that the Romans thought some tumors looked like many-legged crabs. A French descendant of this Latin word was borrowed into English as canker. It is now applied to several plant and animal disorders. In the 14th century the Latin word cancer in the sense of “tumor” was borrowed directly into English, giving us our modern spelling and sense.

Examples of cancer in a Sentence

He was diagnosed with cancer. She learned that she has cancer. Eating certain foods may help reduce the risk of cancer. Advanced cancers are more difficult to treat. I'm a Taurus, but my best friend is a Cancer.
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.
Rather than relying solely on conventional T cells, future treatments may be able to exploit gamma delta T cells to expose a vulnerability in a cancer that has proved exceptionally difficult to treat. — New Atlas, 15 Oct. 2026 The surgery confirmed that the pope has the most common type of lung cancer, known as lung adenocarcinoma, the Vatican said in a medical bulletin late yesterday. — Chicago Tribune, 14 Oct. 2026 Although lung cancer is generally considered a disease among people who are older, lung adenocarcinoma is more likely to occur in younger people than other types of lung cancer. — ABC News, 14 Oct. 2026 The Vatican confirmed Tuesday that the 71-year-old has lung adenocarcinoma, a common form of lung cancer. — Tori Mason, CBS News, 14 Oct. 2026 See All Example Sentences for cancer

Word History

Etymology

Middle English, from Latin (genitive Cancri), literally, crab; akin to Greek karkinos crab, cancer

First Known Use

14th century, in the meaning defined at sense 1a

Time Traveler
The first known use of cancer was in the 14th century

Phrases Containing cancer

Rhymes for cancer

See All Rhymes for cancer

Browse Nearby Words

cancel out
cancer
Cancerian
See all Nearby Words

Cite this Entry

“Cancer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cancer. Accessed 20 Oct. 2026.

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Kids Definition

cancer

noun
can·​cer ˈkan(t)-sər How to pronounce cancer (audio)
1
capitalized : a group of stars between Gemini and Leo usually pictured as a crab
2
capitalized
a
: the fourth sign of the zodiac see zodiac
b
: a person whose sign of the zodiac is Cancer
3
: a tumor that tends to spread locally and to other parts of the body and often causes death if not treated
also : an abnormal state marked by such tumors
4
: a dangerous evil that destroys slowly
cancerous
ˈkan(t)s-(ə-)rəs How to pronounce cancer (audio)
adjective
Etymology

Middle English Cancer "'Crab' star group," from Latin cancer "crab, cancer (disease)"; sense 3 directly from Latin cancer "crab, cancer" — related to canker, chancre

Word Origin
The Latin word cancer, meaning "crab," was also given as a name to several diseases. One of the diseases was the abnormal, spreading mass of tissue we call a tumor. A possible explanation for this extended use of cancer is that the Romans thought some tumors looked like many-legged crabs. A French descendant of this Latin word was borrowed into English as canker. It is now applied to several plant and animal disorders. In the 14th century the Latin word cancer in the sense of "tumor" was borrowed directly into English, giving us our modern spelling and sense.

Medical Definition

cancer

noun
can·​cer ˈkan(t)-sər How to pronounce cancer (audio)
1
: a malignant tumor of potentially unlimited growth that expands locally by invasion and systemically by metastasis
2
: an abnormal state marked by a cancer
cancerous
ˈkan(t)s-(ə-)rəs How to pronounce cancer (audio)
adjective

More from Merriam-Webster on cancer

Thesaurus: All synonyms and antonyms for cancer

Britannica.com: Encyclopedia article about cancer

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