cancer

noun

can·​cer ˈkan(t)-sər 

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 

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

The focus on King Charles’ health due to his cancer diagnosis can sometimes distract from the fact that, since Queen Elizabeth was monarch for so long, her son ascended to the throne way later than anyone expected. —Lizzie Lanuza, StyleCaster, 22 Nov. 2025

Dench, who is now healthy after being diagnosed with breast cancer in 2024, wasn’t well enough to travel for Thanksgiving last year, so the pair opted for a joint Instagram Live. —Melina Khan, USA Today, 22 Nov. 2025

In January, Schlossberg joined a clinical trial of CAR-T-cell therapy, a type of immunotherapy against certain blood cancers. —Escher Walcott, PEOPLE, 22 Nov. 2025

The first human trial – to treat prostate cancer patients – was back in 2008. —New Atlas, 22 Nov. 2025

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

Phrases Containing cancer

• cancer stick
• small-cell lung cancer

Rhymes for cancer

• anser
• answer
• dancer
• lancer
• anticancer
• necromancer
• enhancer
• merganser
• romancer

Kids Definition

cancer

noun

can·​cer ˈkan(t)-sər 

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 

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 

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 

adjective