Columbia Encyclopedia

Search results

500 results found

macular degeneration

(Encyclopedia)macular degeneration, eye disorder causing loss of central vision. The affected area, the macula, lies at the back of the retina and is the part that produces the sharpest vision. The most serious vis...

matrix

(Encyclopedia)matrix, in mathematics, a rectangular array of elements (e.g., numbers) considered as a single entity. A matrix is distinguished by the number of rows and columns it contains. The matrix CE5 is a 2...

Pap test

(Encyclopedia)Pap test, Pap smear, or Papanicolaou test păpˌənēˈkəlou [key], medical procedure used to detect cancer of the uterine cervix (see uterus). A scraping, brushing, or smear, is taken from the surf...

waterway

(Encyclopedia)waterway, natural or artificial navigable inland body of water, or system of interconnected bodies of water, used for transportation, may include a lake, river, canal, or any combination of these. The...

bursitis

(Encyclopedia)bursitis bərsīˈtəs [key], acute or chronic inflammation of a bursa, or fluid sac, located close to a joint. In response to irritation or injury the bursa may become inflamed, causing pain, restric...

threat

(Encyclopedia)threat, in law, declaration of intent to injure another by doing an unlawful act, with a view to restraining his freedom of action. A threat is distinguishable from an assault, for an assault requires...

scale, in cartography

(Encyclopedia)scale, in cartography, the ratio of the distance between two points on a map to the real distance between the two corresponding points portrayed. The scale may be expressed in three ways: numerically,...

scintillation counter

(Encyclopedia)scintillation counter, device for detecting and measuring radiation by means of tiny visible flashes produced by the radiation when it strikes a sensitive substance known as a phosphor (see phosphores...

caribou, in zoology

(Encyclopedia)caribou, name in North America for the genus (Rangifer) of deer from which the Old World reindeer was originally domesticated. Caribou are found in arctic and subarctic regions. They are the only deer...

baldness

(Encyclopedia)baldness, thinning or loss of hair as a result of illness, functional disorder, or hereditary disposition; also known as alopecia. Male pattern baldness, a genetic trait, is the most common cause of b...