Encyclopædia Britannica Australia -

Encyclopedias since 1768

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diffraction ... DiMaggio, Joe

diffraction: the spreading of waves around obstacles. Diffraction takes place with sound; with electromagnetic radiation, such as light, X-rays, and gamma rays; and with very small moving particles such as atoms, neutrons, and electrons, which show wavelike properties. One consequence of ...
diffraction grating: component of optical devices consisting of a surface ruled with close, equidistant, and parallel lines for the purpose of resolving light into spectra. A grating is said to be a transmission or reflection grating according to whether it is transparent ...
diffusion: process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration. A familiar example is the perfume of a flower that quickly permeates ...
diffusion chamber: simple form of cloud chamber, a device used for radiation detection (see cloud chamber).
Digambara: one of the two principal sects of the Indian religion Jainism, whose male ascetics shun all property and wear no clothes. In accordance with their practice of nonviolence, the monks also use a peacock-feather duster to clear their path of ...
Digby: town, seat of Digby county, western Nova Scotia, Canada. It is situated on the isthmus of Digby Neck Peninsula, at the southern end of Annapolis Basin, an inlet of the Bay of Fundy.
Digby, Sir Kenelm: English courtier, philosopher, diplomat, and scientist of the reign of Charles I.
Digenis Akritas: Byzantine epic hero celebrated in folk ballads (Akritic ballads) and in an epic relating his parentage, boyhood adventures, manhood, and death. Based on a historical character who died about 788, the epic, a blend of Greek, Byzantine, and Oriental motifs, ...
digestion: sequence by which food is broken down and chemically converted so that it can be absorbed by the cells of an organism and used to maintain vital bodily functions. This article summarizes the chemical actions of the digestive process. For ...
digestive system disease: any of the diseases that affect the human digestive tract. Such disorders may affect the esophagus, stomach, small intestine, large intestine (colon), pancreas, liver, or biliary tract. A prevalent disorder of the digestive system is gastroesophageal reflux disease (i.e., the ...
digestive system, human: the system used in the human body for the process of digestion. The human digestive system consists primarily of the digestive tract, or the series of structures and organs through which food and liquids pass during their processing into forms ...
digestive system, invertebrate: any of the systems used by invertebrates for the process of digestion. Included are vacuolar and channel-network systems, as well as more specialized saccular and tubular systems.
Digger: any of a group of agrarian communists who flourished in England in 1649-50 and were led by Gerrard Winstanley (q.v.) and William Everard. In April 1649 about 20 poor men assembled at St. George's Hill, Surrey, and began to cultivate ...
Diggs, Annie LePorte: Canadian-born American reformer and politician, an organizer and campaigner in the Populist Movement of the late 19th century.
digit: in anatomy, finger or toe of land vertebrates, the skeleton of which consists of small bones called phalanges. The tips of the digits are usually protected by keratinous structures, such as claws, nails, or hoofs, which may also be used ...
digit malformation: in human physiology, any of the isolated anomalies of the digits (fingers or toes) in an otherwise normal individual or as one symptom of a more generalized genetic abnormality. In polydactyly, having more than the normal number of digits, the ...
digital computer: any of a class of devices capable of solving problems by processing information in discrete form. It operates on data, including magnitudes, letters, and symbols, that are expressed in binary form-i.e., using only the two digits 0 and 1. By ...
Digital Equipment Corporation: American manufacturer that created a new line of low-cost computers, known as minicomputers, especially for use in laboratories and research institutions. Founded in 1957, the company employed more than 120,000 people worldwide at its peak in 1990 and earned more ...
digital sound recording: method of preserving sound in which audio signals are transformed into a series of pulses that correspond to patterns of binary digits (i.e., 0's and 1's) and are recorded as such on the surface of a magnetic tape or optical ...
digitalis: drug obtained from the dried leaves of the common foxglove (Digitalis purpurea) and used in medicine to strengthen contractions of the heart muscle. Belonging to a group of drugs called cardiac glycosides, digitalis is most commonly used ...
diglossia: the coexistence of two forms of the same language in a speech community. Often, one form is the literary or prestige dialect, and the other is a common dialect spoken by most of the population. Such a situation exists in ...
Digne-les-Bains: town, capital of Alpes-de-Haute-Provence departement, Provence-Alpes-Cotes-d'Azur region, southeastern France. It lies 83 miles (134 km) northwest of Cannes by road. Situated on the scenic Route Napoleon, along which Napoleon traveled over the Alps on his return from Elba in 1815, ...
Digul River: river rising on the southern slopes of the Sterren Mountains in east-central Irian Jaya, Indonesia, on the island of New Guinea. The river flows 326 miles (525 km) south and west across a low region of extensive swamps (in the ...
Dihigo, Martin: professional baseball player who became a national hero in his native Cuba. In addition to playing in the Cuban League, Dihigo played in the leagues of the Dominican Republic, Mexico, and Venezuela and in the U.S. Negro leagues. Because of ...
Dijon: city, capital of Cote d'Or departement and of Bourgogne (Burgundy) region, east-central France. The city is 203 miles (326 km) southeast of Paris by road and lies at the confluence of the Ouche and Suzon rivers. Situated at the foot ...
dik-dik: (genus Madoqua), any of several small, delicate African antelopes, family Bovidae (order Artiodactyla), named for the sound it makes when alarmed. The dik-dik stands 30-40 cm (12-16 inches) at the shoulder and weighs 3-5 kg (7-11 pounds). It has an ...
dika nut: edible nut of the dika tree, which is also called the dika bread, or Gabon chocolate, tree (species Irvingia barteri), and is native to western Africa. The nut is used principally for food and oil.
dike: in geology, tabular or sheetlike igneous body that is often oriented vertically or steeply inclined to the bedding of preexisting intruded rocks; similar bodies oriented parallel to the bedding of the enclosing rocks are called sills. A dike set is ...
Dikelocephalus: genus of trilobites (extinct arthropods) that is a useful guide fossil for the Late Cambrian rocks (512 to 505 million years ago) of Europe and North America. Dikelocephalus is distinguished by its broad head, its large and relatively well-developed tail, ...
diksa: rite of consecration that preceded the Vedic sacrifice in ancient India; in later and modern Hinduism, the initiation of a layman by his guru (spiritual guide) into a religious sect.
Dikwa: town and traditional emirate, Borno state, Nigeria. The town lies near the Yedseram River, which flows into Lake Chad, and has road connections to Maiduguri, Bama, Ngala, and Kukawa. Precisely when the town was founded and when its walls (30 ...
dilator muscle: any of the muscles that widen a body part-e.g., in humans, the dilator pupillae, fibres that extend radially through the iris of the eye and contract as available light decreases, thus dilating the pupil. There is also a dilator naris, ...
dilemma: in syllogistic, or traditional, logic, any one of several forms of inference in which there are two major premises of hypothetical form and a disjunctive ("either . . . or") minor premise. For example:
dilemma tale: typically African form of short story whose ending is either open to conjecture or is morally ambiguous, thus allowing the audience to comment or speculate upon the correct solution to the problem posed in the tale. Typical issues raised involve ...
Dili: city and capital of East Timor. It lies on Ombai Strait on the northern coast of Timor island, the easternmost of the Lesser Sunda Islands. Dili is the chief port and commercial centre for East Timor; it also has an ...
diligence: large, four-wheeled, closed French stagecoach employed for long journeys. It was also used in England and was popular in both countries in the 18th and 19th centuries.
Dilke, Sir Charles Wentworth, 2nd Baronet: British statesman and Radical member of Parliament who became a member of the Cabinet in William E. Gladstone's second administration but was ruined at the height of his career when he was cited as corespondent in a divorce suit.
dill: (species Anethum graveolens), fennellike annual or biennial herb of the parsley family (Apiaceae, or Umbelliferae) or its dried, ripe fruit, or seeds, and leafy tops; these are used to season foods, particularly in eastern Europe and Scandinavia. Native to Mediterranean ...
Dill, Sir John Greer: British field marshal who became the British chief of staff during the early part of World War II and, from 1941 to 1944, headed the British joint staff mission to the United States.
Dillard, Annie: American writer best known for her meditative essays on the natural world.
Dillards, the: American bluegrass musicians who took their Ozark Mountain style to California and helped lay the groundwork for country rock as well as for a "progressive" style of bluegrass music. The original members were Douglas Dillard (b. March 6, 1937, East ...
Dilleniales: order of dicotyledonous flowering plants comprising two families (Dilleniaceae and Paeoniaceae), with 11 genera, most of which are trees, shrubs, or woody vines of the tropics and subtropics. The plants are characterized by radially symmetrical, usually bisexual flowers with three ...
Dilleniidae: subclass of flowering plants belonging to the class Magnoliopsida. The subclass Dilleniidae in the system used in this article contains 13 orders, 78 families, and about 25,000 species. Among its members are such plants as the peony, cacao, kapok (also ...
Dillenius, Johann Jakob: botanist who wrote several descriptive works on plants.
Dillinger, John: most famous of all U.S. bank robbers, whose short career of robberies and escapes from June 1933 to July 1934 won media headlines.
Dillon: city, seat (1881) of Beaverhead county, southwestern Montana, U.S., on the Beaverhead River (part of the Jefferson River system). It was founded as Terminus in 1880, with the arrival of the Utah and Northern Railroad, and was renamed (1881) for ...
Dillon: county, eastern South Carolina, U.S. It lies in a fertile tobacco-growing region of the Coastal Plain. North Carolina forms the northeastern border, the Lumber River the southeastern border, and the Great Pee Dee River the southwestern border. The county is ...
Dillon, John: a leader of the Irish Nationalist Party in the struggle to secure Home Rule by parliamentary means. Through the 1880s he was perhaps the most important ally of the greatest 19th-century Irish Nationalist, Charles Stewart Parnell; but after Parnell's involvement ...
Dilmun: Sumerian name of an ancient independent kingdom that flourished c. 2000 BC, plausibly identified with the island in the Persian Gulf now called al-Bahrain. Dilmun is mentioned as a commercial centre in Sumerian economic texts of the 3rd millennium BC, ...
Dilthey, Wilhelm: German philosopher who made important contributions to a methodology of the humanities and other human sciences. He objected to the pervasive influence of the natural sciences and developed a philosophy of life that perceived man in his historical contingency and ...
DiMaggio, Joe: American professional baseball player who was an outstanding hitter and fielder and one of the best all-round players in the history of the game.