a large-scale musical composition on a sacred or semisacred subject, for solo voices, chorus, and orchestra. An oratorio's text is usually based on scripture, and the narration necessary to move ...
the rationale and practice of persuasive public speaking. It is immediate in its audience relationships and reactions, but it may also have broad historical repercussions. The orator may become the ...
emblem of royal power, usually made of precious metal and jewels and consisting of a sphere surmounted by a cross. The ball as a symbol of the cosmos, or of ...
any spider of the family Araneidae (Argiopidae or Epeiridae) of the order Araneida, a large and widely distributed group noted for their orb-shaped webs. More than 2,500 species are known.
American singer-songwriter best remembered for his soaring voice, one of the most operatic in all rock music, and for his carefully crafted ballads of loneliness and heartache.
in astronomy, path of a body revolving around an attracting centre of mass, as a planet around the Sun or a satellite around a planet. In the 17th century, Johannes ...
in chemistry and physics, a mathematical expression, called a wave function, that describes properties characteristic of no more than two electrons in the vicinity of an atomic nucleus or of ...
velocity sufficient to cause a natural or artificial satellite to remain in orbit. Inertia of the moving body tends to make it move on in a straight line, while gravitational ...
any of a series of unmanned U.S. scientific satellites developed to observe cosmic objects from above the Earth's atmosphere. OAO-2, launched Dec. 7, 1968, carried two large telescopes and a ...
any of a series of six unmanned scientific satellites launched by the United States from 1964 to 1969. Equipped with a complex of magnetometers, these orbiting satellites were designed to ...
(Dactylis glomerata), perennial pasture, hay, and forage grass of the family Poaceae. It has flat leaf blades and open, irregular, stiff-branched panicles (flower clusters).
English ecumenical priest who strove for a closer understanding between Protestants and Roman Catholics. He entered Westminster College, Cambridge, to prepare for the Presbyterian ministry and in 1904 was ordained ...
instrumental ensemble of varying size and composition. Although applied to various ensembles found in Western and non-Western music, orchestra in an unqualified sense usually refers to the typical Western music ...
historic town, Tikamgarh district, Madhya Pradesh state, central India, on the Betwa River. The town, surrounded by thick jungle that long made it impregnable, was founded in 1531 and served ...
former Rajput princely state of central India, founded in about 1500. In the early 17th century it was systematically devastated by the forces of the Mughal emperor Shah Jahan following ...
any member of the family Orchidaceae, a group of attractively flowered plants that composes the order Orchidales. There are from 400 to 800 genera of orchids, with at least 15,000 ...
a violet dye obtained from some lichens by fermentation. It is also the term for any lichen that yields orchil (Roccella, Lecanora, Ochrolechin, and Evernia) and refers to any colour ...
genus of orchids, family Orchidaceae, containing as many as 100 species native to Eurasia and North America. Each plant bears a single flower spike with many flowers and has egg-shaped, ...
inflammation and swelling of the testes as a result of infection or physical injury. The testes are a pair of organs located in the scrotum of the male; they produce ...
ancient Boeotian town on a promontory on the north of the Copiac plain. The northernmost Mycenaean fortified town, it was a seat of the Minyae dynastic family and controlled a ...
river in the Kimberley plateau region, northeastern Western Australia. It rises in the Albert Edward Range and follows an easterly and northerly course for 300 mi (500 km) to Cambridge ...
a trial or judgment of the truth of some claim or accusation by various means based on the belief that the outcome will reflect the judgment of supernatural powers and ...
noble Italian family that ruled the town of Forli and neighbouring places in the Romagna during most of the 14th and 15th centuries. Little is known of their rise; a ...
in any of several styles of classical or Neoclassical architecture that are defined by the particular type of column and entablature they use as a basic unit. A column consists ...
in Great Britain, a regulation issued by the sovereign on the advice of the Privy Council; in modern practice, however, an order is issued only upon the advice of ministers, ...
English monk of Saint-Evroult in Normandy, a historian who in his Historia ecclesiastica left one of the fullest and most graphic accounts of Anglo-Norman society in his own day.
town, Kane county, southwestern Utah, U.S., on the East Fork of the Virgin River, at an altitude of 5,250 feet (1,600 metres), 18 miles (29 km) north-northwest of Kanab. Settled ...
in mathematics, an equation relating a function f of one variable to its derivatives. (The adjective "ordinary" here refers to those differential equations involving one variable, as distinguished from such ...
method of philosophical investigation concerned with how verbal expressions are used in a particular, nontechnical, everyday language. The basic source for this school of thought is the later writings of ...
in Christian churches, a rite for the dedication and commissioning of ministers. The essential ceremony consists of the laying of hands of the ordaining minister upon the head of the ...
sculptor who was one of the originators of the Spanish school of Renaissance sculpture. Influenced by the masters of the Italian Renaissance, he evolved his own pure style, which was ...
desert on a plateau in the southern section of the Inner Mongolian autonomous ch'u (region), China. The Ordos fills the area inside the great northern bend of the Huang Ho ...
second oldest period of the Paleozoic Era, thought to have covered the span of time between 505 and 438 million years ago (see ), although radiometric age determinations may range ...
city and port, northern Turkey, on the Black Sea. It lies at the mouth of the Melet River on the eastern slopes of Boztepe (1,800 feet [550 m]), which protects ...
range of hills bounding the Bohemian Massif, extending 100 miles (160 km) along the German-Czech border, and reaching an average width of 25 miles (40 km). The Bohemian (southeastern) side ...
town and capital of Orebro lan (county), south-central Sweden. Orebro lies along the Svart River at its entrance into Lake Hjalmar. One of Sweden's oldest towns, it was already a ...
lan (county) of south-central Sweden. It extends from the Bergslagen mining region in the north to Lake Hjalmar in the east and Lake Vatter in the south. It comprises the ...
flavourful dried leaves and flowering tops of any of various perennial herbs of the mint family (Lamiaceae, or Labiatae), particularly Origanum vulgare, called wild marjoram in northern and central Europe, ...
city, seat (1836) of Ogle county, northern Illinois, U.S. It lies on the Rock River, about 95 miles (155 km) west of Chicago. Early inhabitants of the region included Potawatomi ...
constituent state of the United States of America. To the north of the state's 97,073 square miles (251,419 square kilometres) of land and inland water lies Washington, from which Oregon ...
cave complex in the Siskiyou Mountains of southwestern Oregon, U.S., near the California border. Established in 1909, the monument occupies a surface area of 0.8 square mile (2 square km). ...
city, seat (1843) of Clackamas county, northwestern Oregon, U.S., at Willamette Falls (40 feet [12 metres] high) and the juncture of the Clackamas and Willamette rivers. It forms part of ...
any of several species of the genus Mahonia, evergreen shrubs of the barberry family (Berberidaceae) grown for their ornamental value. M. aquifolium, the typical Oregon grape, is 90 cm (3 ...
public, coeducational institution of higher learning in Portland, Oregon, U.S. It is specifically dedicated to biomedical research and patient medical care and to training health professionals, scientists, and engineers. The ...
in U.S.-Canadian history, dispute over ownership of the Pacific Northwest involving Spain, Russia, the United States, and Great Britain, all of which had established claims based on exploration or settlement ...
public, coeducational institution of higher learning in Corvallis, Oregon, U.S. It is a comprehensive research university with land-, sea-, and space-grant status and awards undergraduate, graduate, and professional degrees. The ...
in U.S. history, one of the great emigrant routes to the Northwest, running from Independence, Mo., to the Columbia River region of Oregon. It crossed about 2,000 miles (3,200 km) ...
public, coeducational institution of higher learning in Eugene, Oregon, U.S. The university comprises colleges of arts and sciences, business, and education; schools of architecture and allied arts, law, music, and ...
morning daily newspaper published in Portland, Oregon, one of the leading dailies of the U.S. Northwest and for many years during the 19th century the only newspaper in the seven ...
French skier and auto racer who won a double championship in the downhill and combined events of Alpine skiing during the 1948 Winter Olympics in St. Moritz, Switzerland. His downhill ...
city in Moscow oblast (province), western Russia, east of Moscow city, along the Klyazma River. Formed in 1917 through the amalgamation of several industrial villages, Orekhovo-Zuyevo is now one of ...
city, Utah county, north-central Utah, U.S., 4 miles (6.5 km) north of Provo. The Provo River flows to the east in Provo River canyon (containing the scenic Bridal Veil Falls), ...
oblast (province), western Russia, occupying an area that extends across the southern end of the Ural Mountains. It stretches from the limestone plateaus of the Obshchy Syrt in the west, ...
city and administrative centre of Orenburg oblast (province), western Russia, on the Ural River at the Sakmara confluence. Founded as a fortress in 1735 at the Ural-Or confluence, where Orsk ...
town, capital of Orense provincia, in the comunidad autonoma ("autonomous community") of Galicia, northwestern Spain, situated along the eastern bank of the Mino River, south-southeast of La Coruna. Its name ...
provincia, northwestern Spain, the only landlocked province in the comunidad autonoma ("autonomous community") of Galicia. It is bounded by Portugal on the south and by the provincias of Pontevedra (west), ...
extinct genus of primates found as fossils in Late Miocene deposits in East Africa and Early Pliocene deposits in southern Europe (11.2 to 3.4 million years ago). Oreopithecus is best ...
French Roman Catholic bishop, scholastic philosopher, economist, and mathematician whose work provided some basis for the development of modern mathematics and science and of French prose, particularly its scientific vocabulary.
trilogy of tragic dramas by the ancient Greek dramatist Aeschylus, first performed in 458 BC. It is his last work and the only complete trilogy of Greek dramas that has ...
in Greek mythology, son of Agamemnon, king of Mycenae (or Argos), and his wife, Clytemnestra. According to Homer, Orestes was away when his father returned from Troy to meet his ...
