tropic of Cancer
Origin of tropic of Cancer
Definition for tropic of cancer (2 of 3)
- 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.
Origin of tropic
Related formsnon·trop·ic, adjectiveun·trop·ic, adjective
Definition for tropic of cancer (3 of 3)
- 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.
- the fourth sign of the zodiac: the cardinal water sign.
- a person born under this sign, usually between June 21 and July 22.
Origin of cancer
British Dictionary definitions for tropic of cancer (1 of 3)
Related formsRelated prefix: carcino-
Derived Formscancerous, adjectivecancerously, adverb
Word Origin for cancer
British Dictionary definitions for tropic of cancer (2 of 3)
noun Latin genitive Cancri (ˈkæŋkriː)
- 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
- Also called: Moonchild a person born during a period when the sun is in this sign
British Dictionary definitions for tropic of cancer (3 of 3)
Word Origin for tropic
Medicine definitions for tropic of cancer
Related formscan′cer•ous (kăn′sər-əs) adj.
Science definitions for tropic of cancer (1 of 4)
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).
Science definitions for tropic of cancer (2 of 4)
Science definitions for tropic of cancer (3 of 4)
Science definitions for tropic of cancer (4 of 4)
Tropic of Cancer
Culture definitions for tropic of cancer (1 of 2)
Tropic of Cancer
Culture definitions for tropic of cancer (2 of 2)
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).