American theoretical physicist and science administrator, noted as director of the Los Alamos laboratory during development of the atomic bomb (1943-45) and as director of the Institute for Advanced Study, ...
fylke (county), south-central Norway. Bisected by Gudbrand's Valley, it extends from Mjosa and Randsfjorden lakes northwestward to the Jotunheimen, Dovrefjell, and Rondane mountains. Much of the fylke is made up ...
American magazine associated with the Harlem Renaissance, published from 1923 to 1949. The editor, Charles S. Johnson, aimed to give voice to black culture, hitherto neglected by mainstream American publishing.
in Pythagorean philosophy, a set of 10 pairs of contrary qualities. The earliest reference is in Aristotle, who said that it was in use among some contemporary Pythagoreans. But Aristotle ...
in astronomy, the circumstance in which two celestial bodies appear in opposite directions in the sky. The Moon, when full, is said to be in opposition to the Sun; the ...
in traditional logic, a diagram exhibiting four forms of a categorical proposition (q.v.), or statement, with the same subject and predicate, together with their pairwise relationships:
private court or household created by Tsar Ivan IV the Terrible (1565) that administered those Russian lands (also known as oprichnina) that had been separated from the rest of Muscovy ...
degeneration of the optic (second cranial) nerve, which carries visual data from the retina of the eye to a relay station in the centre of the brain (the lateral geniculate ...
second cranial nerve that carries sensory nerve impulses from the retina to the visual cortex of the brain. In the eye, the nerve forms from the convergence of visual nerve ...
inflammation of the optic (second cranial) nerve, the nerve that carries visual data from the retina of the eye to a relay station in the centre of the brain for ...
the ability of a substance to rotate the plane of polarization of a beam of light that is passed through it. (In plane-polarized light, the vibrations of the electric field ...
the straight line passing through the geometrical centre of a lens and joining the two centres of curvature of its surfaces. Sometimes the optical axis of a lens is called ...
branch of crystallography that deals with the optical properties of crystals. It is of considerable interest theoretically and has the greatest practical importance. The science of petrography is largely based ...
the apparent reproduction of an object, formed by a lens or mirror system from reflected, refracted, or diffracted light waves. There are two kinds of images, real and virtual. In ...
instrument for making precise measurements for beams of light of such factors as length, surface irregularities, and index of refraction. It divides a beam of light into a number of ...
in physics, description of atomic nuclei as similar to cloudy crystal balls in that, when struck by a beam of particles, they partially absorb the beam, partially scatter it, and ...
in physics, the use of light energy to raise the atoms of a system from one energy level to another. A system may consist of atoms having a random orientation ...
use of an optical system for registering sound on photographic film; it is a technique widely used in making the sound track (q.v.) of motion pictures.
electronic storage medium that uses low-power laser beams to record and retrieve digital (binary) data. In optical-storage technology, a laser beam encodes digital data onto an optical, or laser, disk ...
science concerned with the genesis and propagation of light, the changes that it undergoes and produces, and other phenomena closely associated with it. There are two major branches of optics, ...
(Latin: respectively, "Best Ones," or "Aristocrats", and "Demagogues," or "Populists"), two principal patrician political groups during the later Roman Republic from about 133 to 27 BC. The members of both ...
collection of mathematical principles and methods used for solving quantitative problems in many disciplines, including physics, biology, engineering, economics, and business. The subject grew from a realization that quantitative problems ...
health-care profession concerned with examining the eyes for defects of vision and diagnosing and treating such conditions. Optometrists prescribe and supply eyeglasses, contact lenses, and other optical aids that correct ...
largest cactus genus of the family Cactaceae, native to the New World and featuring the characteristic glochidia-small bristles with backward-facing barbs. The genus is divided into subgroups based on the ...
in ancient Greece, the chief city of the Locri Opuntii. Its site may have been at modern Atalandi or at Kiparissi. Homer in his Iliad mentioned Opus, and Pindar devoted ...
in mosaic, type of decorative pavement work widely used in Byzantium in the 9th century. It utilized tiny, geometrically shaped pieces of coloured stone and glass paste that were arranged ...
(Latin: "English work"), embroidery done in England between about 1100 and about 1350 and of a standard unsurpassed anywhere. The technical skill that was shown by English workers in handling ...
Roman Catholic lay and clerical organization whose members seek personal Christian perfection and strive to implement Christian ideals and values in their occupations and in society as a whole. Theologically ...
metalwork technique developed in Rome and widely used during the 3rd century AD, especially appropriate for making arabesques and other nonrepresentational ornamental designs. Probably of Syrian origin, the technique consists ...
type of mosaic work in which figural patterns are composed of pieces of stone or, sometimes, shell or mother-of-pearl cut in shapes to fit the component parts of the design, ...
in mosaic, type of simple, unpatterned or roughly patterned pavement commonly used in Roman times. It was composed of river gravel, small pieces of stone, or terra-cotta fragments cemented in ...
mosaic technique that involves the use of tesserae (small cubes of stone, marble, glass, ceramic, or other hard material) of uniform size applied to a ground to form pictures and ...
type of mosaic work frequently used in Hellenistic and Roman times, in which part or all of a figural mosaic is made up of small, closely set tesserae (cubes of ...
mountain range that extends about 30 miles (50 km) southward from the southern end of the Great Salt Lake, Utah, U.S., overlooking the Tooele and Salt Lake valleys. The mountains ...
(Latin oraculum from orare, "to pray," or "to speak"), divine communication delivered in response to a petitioner's request; also, the seat of prophecy itself. Oracles were a branch of divination ...
city, capital of Bihor judet (county), northwestern Romania. It lies about 8 miles (13 km) east of the Hungarian border, along the Crisul Repede River where it leaves the western ...
ice-covered volcanic massif, southeastern Iceland. It lies at the southern end of the giant ice field of Vatnajokull (q.v.). Its highest peak, Mount Hvannadals, reaches an elevation of 6,952 feet ...
Hopi pueblo (village), Navajo county, northeastern Arizona, U.S. The pueblo is situated on the narrow, rocky Third Mesa of the Hopi Indian Reservation. It is the unofficial capital of the ...
city, western Kazakhstan, along the Ural (Zhayyq) River. Founded in 1613 or 1622 by Cossacks fleeing a tsarist punitive campaign, it was known as Yaitsky Gorodok until 1775, when its ...
disease characterized by the growth of cancerous cells in the mouth, including the lips. Oral cancer is often associated with cancers of the cavity located behind the tonsils and the ...
private, coeducational institution of higher learning in Tulsa, Oklahoma, U.S. An interdenominational Protestant university, it emphasizes fundamentalist Christian values in its programs. A range of undergraduate programs leading to a ...
in Freudian psychoanalytic theory, initial psychosexual stage during which the developing infant's main concerns are with oral gratification. The oral phase in the normal infant has a direct bearing on ...
dental specialty that deals with the diagnosis and surgical treatment of the diseases, injuries, and defects of the human mouth, jaw, and associated structures. The most common oral surgery procedure ...
city, northwestern Algeria. It lies along an open bay on the Mediterranean Sea coast, about midway between Tangier (Morocco) and Algiers, at the point where Algeria is closest to Spain. ...
city, seat (1852) of Orange county, southeastern Texas, U.S. It lies at the Louisiana state line. Orange is a deepwater port on the Sabine River, which has been canalized to ...
city, Orange county, southern California, U.S. Adjacent to Anaheim (west) and Santa Ana (south), it lies along the Santa Ana River. Part of Rancho Santiago de Santa Ana, the city ...
town (township), New Haven county, southwestern Connecticut, U.S., west of New Haven on the Housatonic River. Originally a part of Milford colony (on land bought from the Paugusset Indians and ...
township, Essex county, northeastern New Jersey, U.S. It lies just west of Newark. Named Mountain Plantations when it was settled in 1678, it was later renamed to honour William, prince ...
town, Vaucluse departement, Provence-Alpes-Cote d'Azur region, southeastern France. It lies in a fertile plain on the left bank of the Rhone River, north of ...
county, eastern Vermont, U.S., bounded to the east by New Hampshire; the Connecticut River constitutes the border. It consists of a piedmont region that includes Butterfield, Knox, and Braintree mountains. ...
any of several species of small trees or shrubs of the genus Citrus of the family Rutaceae and their nearly round fruits, which have leathery and oily rinds and edible, ...
county, southeastern New York state, U.S., located mostly in the Hudson River valley. It is bordered by Pennsylvania to the northwest (the Delaware River constituting the boundary), New Jersey to ...
city, east-central New South Wales, Australia. It is located near the slopes of Mount Canobolas, an extinct volcano. In 1828 the area was named by Sir Thomas Mitchell in memory ...
intersectional American college gridiron football game played for many years on New Year's Day in Miami, Florida. By the late 1990s it was often played on January 2 or 3. ...
historical Boer state in southern Africa that became a province of the Republic of South Africa in 1910. One of the four traditional provinces of South Africa, it was bordered ...
an Irish Protestant and political society, named for the Protestant William of Orange, who, as King William III of Great Britain, had defeated the Roman Catholic king James II.
river in southern Africa, one of the longest rivers on the continent and one of the longest south of the Tropic of Capricorn. After rising in the Lesotho Highlands, less ...
town, northwestern Belize, situated on the left (west) bank of the New River. Established in early colonial times, it was pillaged by hostile Indians in 1872. During the late 19th ...
two church synods held in Orange, France, in 441 and 529. The first, under the presidency of St. Hilary of Arles, dealt mainly with disciplinary matters. The second, and by ...
princely dynasty that derived its name from the medieval principality of Orange, in old Provence in southern France. The dynasty was important in the history of The Netherlands and is ...
member of the cosmopolitan insect family Pieridae (order Lepidoptera), which also includes the white and sulfur butterflies and contains more than 1,000 species. Adults have a wingspan of 37 to ...
county, central South Carolina, U.S. The South Fork Edisto and Edisto rivers form the southwestern boundary, and the North Fork Edisto River flows through the southwestern part of the county. ...
city, seat of Orangeburg county, central South Carolina, U.S. It is situated on the North Fork Edisto River. In 1735 Germans, Swiss, and Dutch established a settlement, naming it for ...
garden building designed for the wintering of exotic shrubs and trees, primarily orange trees. The earliest orangeries were practical buildings that could be completely covered by planks and sacking and ...
(1801), brief conflict in which France and Spain fought against Portugal. The war was brought about by Portugal's refusal in 1800 to accept Napoleon's demands to become a political and ...
the only Asian great ape, found in lowland rainforests on the Southeast Asian islands of Sumatra and Borneo. The orangutan possesses cognitive abilities comparable to those of the gorilla and ...
planned company town in one of the principal gem-diamond-producing areas of the world, extreme southwestern Namibia. It is located near the Atlantic coast about 5 miles (8 km) north of ...
seaport and chief administrative centre of the Caribbean island of Aruba, located on the island's western coast. It is a free port and a petroleum-processing and shipping centre. The enclosed ...
in Christian art, a figure in a posture of prayer, usually standing upright with raised arms. The motif of the orant, which seems to reflect the standard attitude of prayer ...
aboriginal people of the Chota Nagpur region in the state of Bihar, India. They call themselves Kurukh and speak a Dravidian language akin to Gondi and other tribal languages of ...
mining town, east-central Botswana. It is located about 240 miles (385 km) north of Gaborone, the national capital. Situated on the eastern edge of the Kalahari (desert), the town was ...
