orchid Any of the 15,000-35,000 species in 400-800 genera of non- woody perennial plants that make up the family Orchidaceae. Bearing attractive flowers, orchids grow in most of the nonpolar world, espe¬ cially in tropical regions, in soil or on other plants. Hybrids with showy flowers for the commercial trade come from the genera Cattleya,
Cymbidium, Vanda, and Laelia.
Flowers vary widely in size, colour, and shape, but all are bilaterally symmetrical and have three sepals.
Most orchids photosynthesize, but some live on dead organic material or absorb food from a fungus living in their roots. Vanilla is extracted from the seedpod of the genus Vanilla. Many folk medicines, local beverages, and foods are prepared from parts of orchid plants.
orchitis \or-'kI-t9s\ Inflammation and swelling of the testes, caused by infection (most often mumps) or chemical or physical injury. The testicles’ rich blood and lymphatic supply block most infections in the absence of severe injury. Usual symptoms are high fever, sudden pain in the testicle, nausea and vomiting, and swelling, tightness, and tenderness of the gland. Fluids with pus or blood may accumulate in the scrotum, which is gen¬ erally red and thickened. Treatment may include antibiotics, bed rest, support of the testes, compresses, and surgery or drainage.
Orchomenus \6r-'ka-m9-n9s\ Ancient city, northwestern Boeotia, Greece. It was the northernmost fortified town in Mycenaean times and controlled a large part of Boeotia. In c. 550 bc it became one of the first cities to coin money, thereby gaining fame for its wealth. It was frequently attacked and finally destroyed by Thebes in the 4th century bc. Excava¬ tions have revealed that it was an important Neolithic and Bronze Age site, with a beehive temple and palace.
Orczy \'ort-se\, Emmuska (Magdalena Rosalia Marie Josepha Barbara), Baroness (b. Sept. 23, 1865, Tamaors, Hung.—d. Nov. 12, 1947, London, Eng.) Hungarian-born British novel¬ ist. The daughter of a noted musician, she was educated in Brussels and Paris and studied art in London. She became famous as the author of The Scarlet Pimpernel (1905), a swashbuckling adventure set in the era of the French Revolution. Her sequels did not match its great popular success. She also wrote detective stories.
Ord River River, northeastern Western Australia. The Ord rises in the Albert Edward Range and flows east and north to the Cambridge Gulf; it is about 200 mi (320 km) long. Discovered in 1879 by Alexander For¬ rest, it was named for Harry Ord, governor of Western Australia. The Ord River Project is designed to prevent flooding and collect irrigation water.
ordeal In customary law, a test of guilt or innocence in which the accused undergoes dangerous or painful tests believed to be under super¬ natural control. Ordeals by fire or water are the most common. Bums suf¬ fered while passing through fire (as in Hindu custom) or rejection (i.e., being buoyed up) by a body of water (as in witch trials) would be regarded as proof of guilt. In ordeal by combat, as in the medieval duel, the victor is said to win not by his own strength but because supernatural powers have intervened on the side of the right.
order In Classical architecture, any of several styles defined by the par¬ ticular type of column, base, capital, and entablature they use. There are five major orders: Doric, Ionic, and Corinthian (all developed in Greece), and Tuscan and Composite (developed in Rome). The form of the capital is an order’s most distinguishing characteristic. Both the Doric and Ionic orders originated in wooden temples. The Doric is squat and simple. The Ionic, distinguished by the scrolls, or volutes, on its capital, resembles a
Orchid (Polystachya bella).
SVEN SAMEUUS
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order in council ► Orff I 1415
capital I. The Corinthian capital is more ornate, with carved acanthus leaves and scrolls. The Romans modified the Greek orders to produce the Tuscan (a simplified form of the Doric) and Composite (a combination of the Ionic and Corinthian) orders. See also colossal order.
Tuscan
Corinthian
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Composite
Capital styles for the five major orders of Classical architecture.
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order in council In Britain, a regulation traditionally issued by the sovereign on the advice of the Privy Council. In modern practice, an order is issued only on the advice of ministers, and the minister in charge of the department concerned with the order’s subject matter is responsible to Parliament for its contents. Most orders in council today are issued to implement legislation passed by Parliament.
Order of the Garter See Order of the Garter
ordinary differential equation Equation containing derivatives of a function of a single variable. Its order is the order of the highest deriva¬ tive it contains (e.g., a first-order differential equation involves only the first derivative of the function). Because the derivative is a rate of change, such an equation states how a function changes but does not specify the function itself. Given sufficient initial conditions, however, such as a spe¬ cific function value, the function can be found by various methods, most based on integration.
Ordovician X.or-ds-'vi-shonN Period Interval of geologic time, 490- 443 million years ago, the second oldest period of the Paleozoic Era. It follows the Cambrian and precedes the Silurian. During the Ordovician, many of the landmasses were aligned in the tropics. Life was dominated by marine invertebrates, but some forms of land plants may have appeared during the middle of the period. Spores suggesting a tropical terrestrial environment have been found in rocks of that age.
Ordzhonikidze Nor-jan-yik-'yed-zoX, Grigory (Konstantino¬ vich) (b. Oct. 24,1886, Goresha, Russia—d. Feb. 18,1937, Moscow, Rus¬ sia, U.S.S.R.) Russian communist leader. After the Russian Revolution of 1917, he became chairman of the Caucasian bureau (1921) and helped the Red Army conquer Georgia, forcing its merger with Armenia and Azer¬ baijan into the Transcaucasian Federal Republic and then into the Soviet Union. He became a member of the Politburo (1930) and commissar for heavy industry (1932), but in the mid-1930s he opposed Joseph Stalin’s industrial policy. His sudden death was ascribed to natural causes, but Nikita Khrushchev later charged (1956) that Stalin had driven him to suicide.
ore Aggregate of economically important minerals that is sufficiently rich to separate for a profit. Although more than 3,500 mineral species are
known, only about 100 are considered ore minerals. The term originally applied only to metallic minerals (see native element) but now includes such nonmetallic substances as sulfur, calcium fluoride (fluorite), and barium sulfate (barite). Ore is always mixed with unwanted rocks and minerals, known collectively as gangue. The ore and the gangue are mined together and then separated. The desired element is then extracted from the ore. The metal may be still further refined (purified) or alloyed with other metals.
oregano Flavourful dried leaves and flowering tops of any of various perennial herbs of the MINT family, particularly Origanum vulgare. Oregano is an essential ingredient of Mediterranean cuisines; in the U.S., use of oregano rose sharply in the late 20th century, largely because of the popularity of pizza. Native to the Mediterranean and western Asia, the herbs are now naturalized in parts of Mexico and the U.S.
Oregon State (pop., 2000: 3,421,399), U.S., northwestern region. Lying on the Pacific Ocean, it is bordered by Washington, Idaho, Nevada, and California. It covers 97,073 sq mi (251,419 sq km). Its capital is Salem. The Columbia River forms its northern boundary; the Snake River is its upper eastern boundary. The Cascades Range, with Mount Hood, is in western central Oregon. First sighted by Spanish explorers, it was visited by Fran¬ cis Drake in 1579 and by James Cook in 1778. The area was inhabited by many American Indian peoples when in 1792 Capt. Robert Gray explored the Columbia River, giving the U.S. a claim to the region. The river’s mouth was reached by the Lewis and Clark Expedition in 1805. The first white settlement was founded at Astoria in 1811 by the fur trader John J. Astor. Settlement of the area accelerated from c. 1843 with mass migration over the Oregon Trail. It was part of the Oregon Territory and was admitted to the Union as the 33rd state in 1859. The state’s economy is dependent on its forests, farms, and livestock. Salmon and shellfish are the bases of the fishing industry. Centres of population, arts, and education are Portland, Eugene, and Medford.