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Encyclopedias since 1768

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Orsini Family ... Osaka

Orsini Family: one of the oldest, most illustrious, and for centuries most powerful of the Roman princely families. Their origins, when stripped of legend, can be traced back to a certain Ursus de Paro, recorded at Rome in 998. They first became ...
Orsini, Felice: Italian nationalist revolutionary and conspirator who tried to assassinate the French emperor Napoleon III.
Orsk: city, Orenburg oblast (province), western Russia. It lies about 150 miles (240 km) south of Magnitogorsk at the confluence of the Ural and Or rivers. It was founded in 1735 as the fortress of Orenburg (q.v.), which was moved downriver ...
Orsted, Hans Christian: Danish physicist and chemist who discovered that electric current in a wire can deflect a magnetized compass needle, a phenomenon the importance of which was rapidly recognized and which inspired the development of electromagnetic theory.
Orta, Lake: lake in Novara and Verbano-Cusio-Ossola provincie, Piemonte (Piedmont) regione, northwestern Italy, just west of Lake Maggiore, from which it is divided by Mount Mottarone. About 8 miles (13 km) long and 0.75 mile (1.2 km) wide, it has an area ...
Ortega y Gasset, Jose: philosopher and humanist who greatly influenced the cultural and literary renaissance of Spain in the 20th century.
Ortega, Daniel: Nicaraguan guerrilla leader, member of the Sandinista junta that took power in 1979, and from November 1984 to April 1990 the elected president of Nicaragua.
Ortega, Domingo: Spanish matador noted for his daring and for his contribution to the literature of bullfighting.
Ortelius, Abraham: Flemish cartographer and dealer in maps, books, and antiquities, who published the first modern atlas, Theatrum orbis terrarum (1570; Epitome of the Theater of the Worlde).
orthochlorite: subgroup of chlorite minerals. See chlorite.
orthoclase: common alkali feldspar mineral, a potassium aluminosilicate (KAlSi₃O₈); it usually occurs as variously coloured, frequently twinned crystals in granite. Orthoclase is used in the manufacture of glass and ceramics; occasionally, transparent crystals are cut as gems. Orthoclase is primarily important ...
orthodontics: division of dentistry dealing with the prevention and correction of irregularities of the teeth-generally entailing the straightening of crooked teeth or the correcting of a poor bite, or malocclusion (physiologically unacceptable contact of opposing dentition, which may be caused by ...
orthodox: (from Greek orthodoxos, "of the right opinion"), true doctrine and its adherents as opposed to heterodox or heretical doctrines and their adherents. The word was first used in early 4th-century Christianity by the Greek Fathers. Because almost every Christian group ...
Orthodox Church in America: ecclesiastically independent, or autocephalous, church of the Eastern Orthodox communion, recognized as such by its mother church in Russia; it adopted its present name on April 10, 1970.
Orthodox Church of Czechoslovakia: autocephalous, or ecclesiastically independent, member of the Eastern Orthodox communion, created in 1951 by the patriarchate of Moscow.
Orthodox Church of Finland: Eastern Orthodox church, recognized as the second state church of Finland. Most of the Orthodox Finns were originally from Karelia, the southeastern part of Finland that was annexed by the Soviet Union in 1940, which was Christianized by Russian monks ...
Orthodox Church of Poland: ecclesiastically independent member of the Eastern Orthodox communion, established in 1924 to accommodate the 4,000,000 Orthodox Christians residing in the vast Ukrainian and Byelorussian territories acquired by Poland after World War I. As the new political situation made it difficult ...
Orthodox Jewish Congregations of America, Union of: official federation of Jewish Orthodox synagogues in the United States and Canada; its counterpart organization for rabbis is the Rabbinical Council of America.
Orthodox Judaism: the religion of those Jews who adhere most strictly to traditional beliefs and practices. Jewish Orthodoxy resolutely refuses to accept the position of Reform Judaism that the Bible and other sacred Jewish writings contain not only eternally valid moral principles ...
Orthodoxy, Autocracy, and Nationality: in Russian history, slogan created in 1832 by Count Sergey S. Uvarov, minister of education 1833-49, that came to represent the official ideology of the imperial government of Nicholas I (reigned 1825-55) and remained the guiding principle behind government policy ...
Orthodoxy, Feast of: feast celebrated on the first Sunday of Lent by the Eastern Orthodox Church and Eastern Catholics of the Byzantine Rite to commemorate the return of icons (sacred images) to the churches (843) and the end of the long iconoclastic controversy. ...
orthogenesis: theory that successive members of an evolutionary series become increasingly modified in a single undeviating direction. That evolution frequently proceeds in orthogenetic fashion is undeniable, though many striking features developed in an orthogenetic group appear to have little if any ...
orthogonal trajectory: family of curves that intersect another family of curves at right angles (see ). Such families of mutually orthogonal curves occur in such branches of physics as electrostatics, in which the lines of force and the lines of constant potential ...
orthographic projection: common method of representing three-dimensional objects, usually by three two-dimensional drawings, in each of which the object is viewed along parallel lines that are perpendicular to the plane of the drawing. For example, an orthographic projection of a house typically ...
orthonectid: any of a class (Orthonectida) of rare wormlike parasites of various marine invertebrates; they are sometimes included in the mesozoans, a group regarded as intermediate between protozoans (single-celled animals) and metazoans (multicellular animals). See mesozoan.
orthopedics: medical specialty concerned with the preservation and restoration of function of the skeletal system and its associated structures, i.e., spinal and other bones, joints, and muscles.
orthopteran: broadly, any member of one of four insect orders. Orthopteran has come to be regarded as the common name for these related groups, which exhibit considerable morphological, physiological, and paleontological diversity. Although sometimes the insects are combined into the order ...
orthopyroxene: any of a series of common silicate minerals in the pyroxene family. Orthopyroxenes typically occur as fibrous or lamellar (thin-plated) green masses in igneous and metamorphic rocks and in meteorites.
orthorhombic system: one of the structural categories systems to which crystalline solids can be assigned. Crystals in this system are referred to three mutually perpendicular axes that are unequal in length. If the atoms or atom groups in the solid are represented ...
Ortigao, Jose Duarte Ramalho: Portuguese essayist and journalist known for his mastery of Portuguese prose and his critical reflections on his native land.
Ortiz, Fernando: anthropologist, essayist, and philologist who pioneered in the study of neo-African cultures in the Americas, particularly in Cuba.
ortolan: (Emberiza hortulana), Eurasian garden and field bird of the subfamily Emberizinae, family Fringillidae. It grows fat in autumn, when large flocks gather for migration to northern Africa and the Middle East, and at that season it is a table delicacy. ...
Orton, Joe: British playwright noted for his outrageous and macabre farces.
Ortona: town, Chieti province, Abruzzi region, central Italy, on a promontory 230 feet (70 m) above sea level, on the Adriatic coast, about 11 miles (18 km) southeast of Pescara. An ancient settlement, it was placed by the 1st-century-BC Greek geographer ...
Orumiyeh: city, extreme northwestern Iran. It lies just west of Lake Urmia on a large fertile plain that yields grains, fruits, tobacco, and other crops. The population is mainly Azeri Turkish, with Kurdish, Assyrian Christian, and Armenian minorities. The remains of ...
Oruro: city, west-central Bolivia. It lies at 12,150 feet (3,702 m) above sea level in the Altiplano region, 30 miles (48 km) north of Poopo Lake. Founded in 1606 as Real Villa de San Felipe de Austria ("Royal Town of St. ...
Orvieto: town, Terni provincia, in the Umbria regione of central Italy. The town is situated atop an isolated rock 640 feet (195 m) above the junction of the Paglia and Chiana rivers. An Etruscan and later a Roman city (in late ...
Orvieto ware: Italian maiolica, a tin-glazed earthenware produced originally at Orvieto, in Umbria, from the 13th century onward. It was copied from, or inspired by, the faience produced in Paterna, Spain. The most common colours of Orvieto ware are the green and ...
Orwell, George: English novelist, essayist, and critic famous for his novels Animal Farm (1945) and Nineteen Eighty-four (1949), the latter a profound anti-Utopian novel that examines the dangers of totalitarian rule.
Ory, Kid: American trombonist and composer who was perhaps the first musician to codify, purely by precept, the role of the trombone in classic three-part contrapuntal jazz improvisation. Ory is often remembered as a "tailgate" trombonist, one whose style of playing fills ...
Oryol: oblast (region), western Russia. It occupies an area of rolling hills of the Central Russian Upland, into which are cut many broad, shallow river valleys. The greater part is in the basin of the upper Oka River. ...
Oryol: city and administrative centre of Oryol oblast (region), western Russia. It is located on the headwaters of the Oka River at its confluence with the Orlik River. Founded in 1564 as a fortress of the Muscovite State ...
oryx: (genus Oryx), any of four large antelopes (family Bovidae, order Artiodactyla) living in herds on deserts and dry plains of Africa and Arabia.
Orzeszkowa, Eliza: Polish novelist and a leading writer of the Positivist period (the Polish Positivists took their name from Auguste Comte's philosophy but were themselves mainly utilitarians). Questions of education, independence, and marriage in Orzeszkowa's works were eventually overshadowed by issues such ...
Osa: city and administrative centre of Osa rayon (sector), Perm oblast (province), Russia, on the left bank of the Kama River near its confluence with the Tulva River. The city is about 60 miles (100 km) southwest of the city of ...
Osa Peninsula: peninsula, southern Costa Rica, bounded on the northwest by Coronado Bay, on the west by the Pacific Ocean, and on the east by the Gulf of Dulce. Costa Rica's second largest peninsula, Osa measures about 20 miles (30 km) northeast-southwest ...
Osage: North American Indian tribe of the Dhegiha branch of the Siouan linguistic stock. They are now concentrated on a reservation in northeastern Oklahoma. Like other members of this subgroup (the Omaha, Ponca, Kansa, and Quapaw), the Osage migrated westward from ...
Osage orange: (Maclura pomifera), thorny tree with large, yellow-green, wrinkled fruit and a milky sap that can produce dermatitis in humans. It is the only species of its genus in the mulberry family (Moraceae). It is native to the south-central United States ...
Osage River: river rising as the Marais des Cygnes (French: "Swan Marshes") in the Flint Hills near Eskridge, Kan., U.S. It becomes the Osage (named for the Osage Indians) after its junction with the Little Osage near Rich Hill, Mo., and then ...
Osaka: fu (urban prefecture), Honshu, Japan. It is bordered by Kyoto urban prefecture (north) and by the ken (prefectures) of Hyogo (northwest), Nara (east), and Wakayama (south) and by Osaka Bay (southeast). It includes the ...
Osaka: city and capital of Osaka fu (urban prefecture), south-central Honshu, Japan. The city, together with its neighbouring city Kobe and nearby Kyoto, are the centres of the Keihanshin Industrial Zone (q.v.), the second largest urban and industrial agglomeration in Japan.