tropic of Cancer
- See under tropic(def 1a).
Origin of tropic of Cancer
- either of two corresponding parallels of latitude on the terrestrial globe, one (tropic of Cancer) about 23½° N, and the other (tropic of Capricorn) about 23½° S of the equator, being the boundaries of the Torrid Zone.
- the tropics,the regions lying between and near these parallels of latitude; the Torrid Zone and neighboring regions.
- Astronomy. either of two circles on the celestial sphere, one lying in the same plane as the tropic of Cancer, the other in the same plane as the tropic of Capricorn.
- of, pertaining to, characteristic of, or occurring in the tropics; tropical: romance under the tropic skies of Old Mexico.
Origin of tropic
- a malignant and invasive growth or tumor, especially one originating in epithelium, tending to recur after excision and to metastasize to other sites.
- any disease characterized by such growths.
- any evil condition or thing that spreads destructively; blight.
- genitive Can·cri [kang-kree] /ˈkæŋ kri/. (initial capital letter) Astronomy. the Crab, a zodiacal constellation between Gemini and Leo.
- (initial capital letter) Astrology.
- the fourth sign of the zodiac: the cardinal water sign.
- 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
- 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
- astronomy a small faint zodiacal constellation in the N hemisphere, lying between Gemini and Leo on the ecliptic and containing the star cluster Praesepe
- Also called: the Crabthe 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
- Also called: Moonchilda person born during a period when the sun is in this sign
- tropic of Cancer See tropic (def. 1)
- astrology born under or characteristic of Cancer
- (sometimes capital) either of the parallel lines of latitude at about 23 1/2 °N (tropic of Cancer) and 23 1/2 °S (tropic of Capricorn) of the equator
- the tropics (often capital) that part of the earth's surface between the tropics of Cancer and Capricorn; the Torrid Zone
- astronomy either of the two parallel circles on the celestial sphere having the same latitudes and names as the corresponding lines on the earth
- a less common word for tropical
Word Origin and History for tropic-cancer
late 14c., "either of the two circles in the celestial sphere which describe the northernmost and southernmost points of the ecliptic," from Late Latin tropicus "of or pertaining to the solstice" (as a noun, "one of the tropics"), from Latin tropicus "pertaining to a turn," from Greek tropikos "of or pertaining to a turn or change, or to the solstice" (as a noun, "the solstice"), from trope "a turning" (see trope).
The notion is of the point at which the sun "turns back" after reaching its northernmost or southernmost point in the sky. Extended 1520s to the corresponding latitudes on the earth's surface (23 degrees 28 minutes north and south); meaning "region between these parallels" is from 1837. Tropical "hot and lush like the climate of the tropics" is first attested 1834.
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.
- Any of various malignant neoplasms characterized by the proliferation of anaplastic cells that tend to invade surrounding tissue and metastasize to new body sites.
- The pathological condition characterized by such growths.
- 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.
- A malignant tumor.
A Closer Look: 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.
- Either of the two parallels of latitude representing the points farthest north and south at which the Sun can shine directly overhead. The northern tropic is the Tropic of Cancer and the southern one is the Tropic of Capricorn.
- tropics. The region of the Earth lying between these latitudes. The tropics are generally the warmest and most humid region of the Earth. Also called Torrid Zone
Tropic of Cancer
- The parallel of latitude approximately 23°27′ north. It forms the boundary between the Torrid and North Temperate zones.
Tropic of Cancer
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).