cancer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various malignant neoplasms characterized by the proliferation of anaplastic cells that tend to invade surrounding tissue and metastasize to new body sites.
• noun The pathological condition characterized by such growths.
• noun A pernicious, spreading evil.

from The Century Dictionary.

• To corrode or eat into, in the manner and with the steadily destructive persistency of a cancer.
• noun [capitalized] [NL.] In zoology, the typical genus of brachyurous decapodous crustaceans of the family Cancridæ: formerly more than conterminous with the order Decapoda, now restricted to the common edible crab of Europe, C. pagurus, and its immediate congeners. See crab.
• noun [capitalized] In astronomy, a constellation and also a sign of the zodiac, represented by the form of a crab, and showing the limits of the sun's course northward in summer; hence, the sign of the summer solstice (marked ♋).
• noun In pathology, a malignant tumor technically named carcinoma (which see); also, by extension, any malignant tumor, as one of certain adenomata and sarcomata.
• noun A plant, possibly cancerwort.
• noun The term cancer, as commonly employed, includes those new growths which possess certain attributes that render them especially dangerous to life, and which are therefore called malignant. Malignant tumors growby infiltration and destruction of the surrounding tissues, and are characterized by a tendency to recur after removal, by the property of spreading to other parts of the body by a process of dissemination known as metastasis, and by producing a general disturbance of health termed cachexia. From the standpoint, of the pathologist two chief groups of cancerous tumors are recognized: the carcinomata, or true cancers, and the sarcomata. The fundamental difference between these two is the fact that carcinoma originates in the epithelial tissues of the body, whereas sarcoma develops from the connective tissues. This difference in origin gives rise to certain structural characteristics which enable the microscopist readily to distinguish one type from the other. Carcinoma is rare before the age of thirty; it is somewhat commoner in women than in men; and it is most often seen in the uterus, skin, breast, and stomach. Sarcoma is a disease of early adult life, is more prone to attack men than women, and is commonly found in the subcutaneous tissue, bony structures, and lymph-nodes. Carcinoma is conveyed from one part of the body to another through the lymphatic vessels, sarcoma by way of the blood-stream. In spite of an enormous amount of research devoted to this subject, the exciting cause of cancer is still unknown. The influences of heredity, climate, food, race, social condition, and local injury have all been invoked as factors concerned, but without arriving at any degree of certainty. The theory referring the developmentof malignant tumors to the presence of minute animal or vegetable organisms has numerous adherents, but it has not been definitely established, and many prominent authorities consider that the explanation is to be sought for in a disturbance of some still undiscovered fundamental law governing the growth of cells. Although it appears that cancer is increasing somewhat in frequency, the percentage of cures is increasing much more rapidly, owing to the earlier diagnoses and more thorough operations which are now possible. Extirpation by the knife as promptly and as completely as possible, when the growth is accessible, is regarded as the method of treatment that offers the greatest hope of a cure; but the employment of the X-rays or other form of radioactivity has in a number of instances given excellent results.
• noun Figuratively, a moral or social evil likened to a cancer in its malignant character and corroding tendency: as, “sloth is a cancer,”

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A genus of decapod Crustacea, including some of the most common shore crabs of Europe and North America, as the rock crab, Jonah crab, etc. See crab.
• noun The fourth of the twelve signs of the zodiac. The first point is the northern limit of the sun's course in summer; hence, the sign of the summer solstice. See Tropic.
• noun A northern constellation between Gemini and Leo.
• noun (Med.) Formerly, any malignant growth, esp. one attended with great pain and ulceration, with cachexia and progressive emaciation. It was so called, perhaps, from the great veins which surround it, compared by the ancients to the claws of a crab. The term is now restricted to such a growth made up of aggregations of epithelial cells, either without support or embedded in the meshes of a trabecular framework.
• noun cells once believed to be peculiar to cancers, but now know to be epithelial cells differing in no respect from those found elsewhere in the body, and distinguished only by peculiarity of location and grouping.
• noun (Bot.) the name of several low plants, mostly parasitic on roots, as the beech drops, the squawroot, etc.
• noun See Tropic.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun medicine, oncology, pathology A disease in which the cells of a tissue undergo uncontrolled (and often rapid) proliferation.
• noun figuratively Something which spreads within something else, damaging the latter.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (astrology) a person who is born while the sun is in Cancer
• noun type genus of the family Cancridae
• noun the fourth sign of the zodiac; the sun is in this sign from about June 21 to July 22
• noun any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream
• noun a small zodiacal constellation in the northern hemisphere; between Leo and Gemini