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[kan-ser] /ˈkæn sər/
  1. a malignant and invasive growth or tumor, especially one originating in epithelium, tending to recur after excision and to metastasize to other sites.
  2. any disease characterized by such growths.
any evil condition or thing that spreads destructively; blight.
genitive Cancri
[kang-kree] /ˈkæŋ kri/ (Show IPA).
(initial capital letter) Astronomy. the Crab, a zodiacal constellation between Gemini and Leo.
(initial capital letter) Astrology.
  1. the fourth sign of the zodiac: the cardinal water sign.
  2. a person born under this sign, usually between June 21 and July 22.
(initial capital letter) tropic of. See under tropic (def 1a).
Origin of cancer
1350-1400; Middle English < Latin: literally, crab; Latin stem cancr-, dissimilated from *carcr-, with *carc-r- akin to Greek karkínos, Sanskrit karkata crab; see canker
Related forms
cancerous, adjective
cancered, adjective
cancerously, adverb
cancerousness, noun
noncancerous, adjective
uncancerous, adjective
2. sickness, evil, plague, scourge. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for cancerous


any type of malignant growth or tumour, caused by abnormal and uncontrolled cell division: it may spread through the lymphatic system or blood stream to other parts of the body
the condition resulting from this
an evil influence that spreads dangerously
prefix carcino-
Derived Forms
cancerous, adjective
cancerously, adverb
Word Origin
C14: from Latin: crab, a creeping tumour; related to Greek karkinos crab, Sanskrit karkata


noun (Latin genitive) Cancri (ˈkæŋkriː)
(astronomy) a small faint zodiacal constellation in the N hemisphere, lying between Gemini and Leo on the ecliptic and containing the star cluster Praesepe
  1. Also called the Crab. the fourth sign of the zodiac, symbol ♋, having a cardinal water classification and ruled by the moon. The sun is in this sign between about June 21 and July 22
  2. Also called Moonchild. a person born during a period when the sun is in this sign
tropic of Cancer, See tropic (sense 1)
(astrology) born under or characteristic of Cancer
Also (for senses 2b, 4) Cancerian (kænˈsɪərɪən)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for cancerous

1560s, from cancer + -ous.



Old English cancer "spreading sore, cancer" (also canceradl), from Latin cancer "a crab," later, "malignant tumor," from Greek karkinos, which, like the Modern English word, has three meanings: crab, tumor, and the zodiac constellation (late Old English), from PIE root *qarq- "to be hard" (like the shell of a crab); cf. Sanskrit karkatah "crab," karkarah "hard;" and perhaps cognate with PIE root *qar-tu- "hard, strong," source of English hard.

Greek physicians Hippocrates and Galen, among others, noted similarity of crabs to some tumors with swollen veins. Meaning "person born under the zodiac sign of Cancer" is from 1894. The sun being in Cancer at the summer solstice, the constellation had association in Latin writers with the south and with summer heat. Cancer stick "cigarette" is from 1959.

Online Etymology Dictionary, © 2010 Douglas Harper
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cancerous in Medicine

cancer can·cer (kān'sər)

  1. Abbr. CA Any of various malignant neoplasms characterized by the proliferation of anaplastic cells that tend to invade surrounding tissue and metastasize to new body sites.

  2. The pathological condition characterized by such growths.

can'cer·ous (kān'sər-əs) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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cancerous in Science
  1. A disease characterized by any of various malignant neoplasms composed of abnormal cells that tend to proliferate rapidly and invade surrounding tissue. Without treatment such as chemotherapy or radiation, cancer cells can metastasize to other body sites and cause organ failure and death.

  2. A malignant tumor.

Our Living Language  : The human immune system often fights off stray cancer cells just as it does bacteria and viruses. However, when cancer cells establish themselves in the body with their own blood supply and begin replicating out of control, cancer becomes a threatening neoplasm, or tumor. It takes a minimum of one billion cancer cells for a neoplasm to be detectable by conventional radiology and physical examinations. Cancer, which represents more than 100 separate diseases, destroys tissues and organs through invasive growth in a particular part of the body and by metastasizing to distant tissues and organs through the bloodstream or lymph system. Heredity, lifestyle habits (such as smoking), and a person's exposure to certain viruses, toxic chemicals, and excessive radiation can trigger genetic changes that affect cell growth. The altered genes, or oncogenes, direct cells to multiply abnormally, thereby taking on the aggressive and destructive characteristics of cancer. Treatments such as surgery, chemotherapy, and radiation are effective with many cancers, but they also end up killing healthy cells. Gene therapy attempts to correct the faulty DNA that causes the uncontrolled growth of cancer cells. Researchers are investigating other treatments, such as immunotherapy (the stimulation of the body's natural defenses), vectorization (aiming chemicals specifically at cancer cells), and nanotechnology (targeting cancer cells with minute objects the size of atoms).
A faint constellation in the Northern Hemisphere near Leo and Gemini. Cancer (the Crab) is the fourth sign of the zodiac.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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cancerous in Culture

cancer definition

A disease characterized by rapid growth of cells in the body, often in the form of a tumor. Cancer is invasive — that is, it can spread to surrounding tissues. Although this disease is a leading cause of death in the United States, research has provided considerable insight into its many causes (which may include diet, viruses, or environmental factors) and options for treatment (which include radiation, chemotherapy, surgery, and possibly gene therapy).

Note: The term cancer is often used to describe a nonmedical condition that is undesirable, destructive, and invasive: “Watergate was a cancer on the presidency.”
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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