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Ontario ... Oppenheim, E. Phillips

Ontario: second largest province of Canada in area. It occupies the strip of the Canadian mainland lying between Hudson and James bays on the north and the St. Lawrence River-Great Lakes ...
Ontario Science Centre: in Toronto, Ont., Can., a science and technology museum. Founded in 1964, the centre offers major collections in aeronautics, agriculture, anatomy, botany, mineralogy, textiles, and other areas. It also makes ...
Ontario, Lake: smallest and most easterly of the Great Lakes of North America. It is bounded on the north by Ontario (Can.) and on the south by New York (U.S.). The lake ...
ontology: the theory or study of being as such; i.e., of the basic characteristics of all reality. Though the term was first coined in the 17th century, ontology is synonymous with ...
Onverwacht series: division of Archean rocks (the Archean Eon lasted from 3.96 to 2.5 billion years ago) in the Swaziland region of southern Africa. The Onverwacht series is well known from exposures ...
onyx: striped, semiprecious variety of the silica mineral agate with white and black alternating bands. Onyx is used in carved cameos and intaglios because its layers can be cut to show ...
Oodnadatta: town, northern South Australia. It lies on the Neales River, southwest of the Simpson Desert. Founded in 1890, Oodnadatta served as the northern terminus of the Central Australian Railway (until ...
oogenesis: in the human female reproductive system, growth process in which the primary egg cell (or ovum) becomes a mature ovum. In any one human generation, the egg's development starts before ...
Ooka Makoto: prolific Japanese poet and literary critic who was largely responsible for bringing contemporary Japanese poetry to the attention of the Western world.
Ooka Shohei: Japanese novelist famous for his depiction of the fate of Japanese soldiers during World War II.
Ooka Tadasuke: highly respected Japanese judge of the Tokugawa period (1603-1867).
oolite: ovoid or spherical crystalline deposit with a concentric or radial structure; most are composed of calcium carbonate, but some are composed of silica, siderite, calcium phosphate, iron silicate, or iron ...
Oomycetes: class of fungi (kingdom Fungi) distinguished by their production of asexual reproductive cells, called zoospores, that can move through the use of one or two whiplike swimming structures (flagella). New ...
Oort cloud: immense, roughly spherical cloud of icy small bodies that are inferred to revolve around the Sun at distances typically more than 1,000 times that of the orbit of Pluto, the ...
Oort, Jan Hendrik: Dutch astronomer who was one of the most important figures in 20th-century efforts to understand the nature of the Milky Way Galaxy.
ooze: pelagic (deep-sea) sediment of which at least 30 percent is composed of the skeletal remains of microscopic floating organisms. Oozes are basically deposits of soft mud on the ocean floor. ...
Op art: branch of mid-20th-century geometric, abstract art that deals with optical illusion. Achieved through the systematic and precise manipulation of shapes and colours, the effects of Op art can be based ...
opah: large marine fish of the family Lampridae (order Lampridiformes), widely distributed in warm oceans. A deep-bodied fish with a small, toothless mouth, the opah grows to a length of about ...
opal: silica mineral extensively used as a gemstone, a submicrocrystalline variety of cristobalite (q.v.). In ancient times opal was included among the noble gems and was ranked second only to emerald ...
opaline glass: usually opaque glass or crystal, either white or coloured, made in France between approximately 1810 and 1890. Opaline resembles the milk glass of 16th-century Venice and the opaque, white glass ...
opalinid: (subphylum Opalinata), any of about 150 protozoans found in the intestinal tracts of amphibians and some other animals. The nuclei of opalinids vary in number from two (e.g., Zelleriella) to ...
Opalinski, Krzysztof: Polish statesman and writer who was a noted satirist.
Oparin, Aleksandr: Russian biochemist noted for his studies on the origin of life from chemical matter. By drawing on the insights of chemistry, he extended the Darwinian theory of evolution backward in ...
Opatija: resort town, one of the best-known coastal resorts in Istria, republic of Croatia, situated on the Kvarner (gulf) of the Adriatic Sea. The town's name derives from the old Benedictine ...
Opava: city, Severomoravsky kraj (region), eastern Czech Republic. It lies along the Opava River near the Polish border and is northwest of Ostrava, from which it is separated by part of ...
OPEC: multinational organization that was established to coordinate the petroleum policies of its members and to provide member states with technical and economic aid.
Opel AG: German automotive company, a wholly owned subsidiary of the U.S. General Motors Corporation, specializing in the manufacture of passenger cars, minibuses, and light vans. Headquarters are in Russelsheim, Ger.
Opel, Fritz von: German automotive industrialist who took part, with Max Valier and Friedrich Wilhelm Sander, in experiments with rocket propulsion for automobiles and aircraft.
Opelika: city, seat (1866) of Lee county, eastern Alabama, U.S. It is situated about 15 miles (24 km) west of the Chattahoochee River, adjacent to Auburn.
Opelousas: city, seat (1805) of St. Landry parish, south-central Louisiana, U.S. It lies on the Gulf Coastal Plain, 20 miles (32 km) north of Lafayette. Founded in 1720 as a French ...
open cluster: in astronomy, any group of young stars held together by mutual gravitation. See star cluster.
Open Door policy: statement of principles initiated by the United States (1899, 1900) for the protection of equal privileges among nations trading with China and in support of Chinese territorial and administrative integrity. ...
Open Range: in U.S. history, the areas of public domain north of Texas where from about 1866 to 1890 more than 5,000,000 cattle were driven to fatten and be shipped off to ...
open stage: theatrical stage without a proscenium, projecting into the audience and surrounded on three sides by the audience. The open stage was used in the corrales of Spain's Golden Age of ...
Open University: British experiment in higher education for adults. It opened in January 1971 with headquarters at the new town of Milton Keynes, Buckinghamshire. There are no academic prerequisites for enrollment in ...
open-field system: basic community organization of cultivation in European agriculture for 2,000 years or more. Its best-known medieval form consisted of three elements: individual peasant holdings in the form of strips scattered ...
open-heart surgery: any surgical procedure that requires an incision into the heart, exposing one or more of the cardiac chambers. The most common open-heart operations are for repair of valvular disease and ...
open-hearth process: steelmaking technique that for most of the 20th century accounted for the major part of all steel made in the world. William Siemens, a German living in England in the ...
open-market operation: any of the purchases and sales of government securities and sometimes commercial paper by the central banking authority for the purpose of regulating the money supply and credit conditions on ...
open-pit mining: surface mining (q.v.) to obtain minerals other than coal.
open-source software: computer software whose source code is put into the public domain, subject to the restriction that any improvements or derived software also include the source code and be put into ...
opencast mining: surface mining (q.v.) to obtain minerals other than coal.
opera: a drama set to music and made up of vocal pieces with orchestral accompaniment and with orchestral overtures and interludes. In some operas, such as those by Richard Wagner, the ...
Opera: Paris opera house designed by Charles Garnier. The building, considered one of the masterpieces of the Second Empire style, was begun in 1861 and opened with an orchestral concert on ...
opera buffa: (Italian: "comic opera"), genre of comic opera originating in Naples in the mid-18th century. It developed from the intermezzi, or interludes, performed between the acts of serious operas. Opera buffa ...
opera seria: (Italian: "serious opera"), style of Italian opera dominant in 18th-century Europe. It emerged in the late 17th century, notably in the work of Alessandro Scarlatti and other composers working in ...
opera-comique: French form of opera in which spoken dialogue alternates with self-contained musical numbers. The earliest examples of opera-comique were satiric comedies with interpolated songs, but the form later developed into ...
operating system: program that manages a computer's resources, especially the allocation of those resources among other programs. Typical resources include the central processing unit (CPU), computer memory, file storage, input/output (I/O) devices, ...
operations research: application of scientific methods to the management and administration of organized military, governmental, commercial, and industrial processes.
operator: in mathematics, any symbol that indicates an operation to be performed. Examples are x (which indicates the square root is to be taken) and ddx (which indicates differentiation with respect ...
operetta: musical-dramatic production similar in structure to an opera but characteristically having a romantically sentimental plot interspersed with songs, orchestral music, and rather elaborate dancing scenes, along with the spoken dialogue. ...
operon: genetic regulatory system found in bacteria and their viruses in which genes coding for functionally related proteins are clustered along the DNA. This feature allows protein synthesis to be controlled ...
Opet: ancient Egyptian festival of the New Year. In the celebration of Opet, the god Amon together with Mut, his consort, and Khons, their son, made a ritual journey from their ...
ophicleide: brass wind musical instrument with a cup-shaped mouthpiece and padded keys, the bass version of the old keyed bugle. The name (from Greek ophis and kleid, "serpent" and "key") alludes ...
Ophioglossaceae: only family in the fern order Ophioglossales, a primitive group not closely related to other ferns. The family contains three genera and about 55 species. Its members are characterized by ...
Ophir: unidentified region famous in Old Testament times for its fine gold. The geographic list of Genesis 10 apparently places it in Arabia, but in the time of Solomon (c. 920 ...
Ophite: (from Greek ophis, "serpent"), member of any of several Gnostic sects that flourished in the Roman Empire during the 2nd century AD and for several centuries thereafter. A variety of ...
Ophrys: genus of orchids, family Orchidaceae, containing approximately 30 species of plants native to Eurasia and North Africa. All have metallic-coloured, hairy flowers that resemble insects. Each plant is less than ...
ophthalmology: medical specialty dealing with the diagnosis and treatment of diseases and disorders of the eye. The first ophthalmologists were oculists. These paramedical specialists practiced on an itinerant basis during the ...
ophthalmoplegia: paralysis of the extraocular muscles, which control the movements of the eye and of the pupil. Ophthalmoplegia usually involves either the third (oculomotor), fourth (trochlear), or sixth (abducent) cranial nerves. ...
ophthalmoscope: instrument for inspecting the interior of the eye, invented in 1851 by the German physiologist Hermann von Helmholtz. The device consists of a strong light that can be directed into ...
Ophuls, Max: German motion-picture director whose mastery of fluid camera movement gave his films a characteristic lyrical flow. He was one of the first truly international directors, sensitive to national differences and ...
Opie, Eugene Lindsay: American pathologist who conducted important research on the causes, transmission, and diagnosis of tuberculosis and on immunization against the disease.
Opie, John: English portrait and historical painter popular in England during the late 18th century.
Opik, Ernest Julius: Estonian astronomer best known for his studies of meteors and meteorites, and whose life work was devoted to understanding the structure and evolution of the cosmos.
opisthobranch: any marine gastropod of the approximately 2,000 species of the subclass Opisthobranchia. These gastropods, sometimes called sea slugs, breathe either through gills, which are located behind the heart, or through ...
Opitz, Martin: German poet and literary theorist who introduced foreign literary models and rules into German poetry.
opium: narcotic drug that is obtained from the unripe seedpods of the opium poppy (Papaver somniferum), a plant of the family Papaveraceae. (See poppy.) Opium is obtained by slightly incising the ...
opium trade: in Chinese history, the traffic that developed in the 18th and 19th centuries in which Western nations, mostly Great Britain, exported opium grown in India and sold it to China. ...
Opium Wars: two trading wars in the mid-19th century in which Western nations gained commercial privileges in China. The first Opium War (1839-42) was between China and Britain, and the second Opium ...
Opole: city, capital of Opolskie wojewodztwo (province), southwestern Poland, situated on the Oder River. Opole began as the home of the Slavic Opolanie tribe; the earliest mention of ...
Opolskie: wojewodztwo (province), southern Poland. It is bordered by the provinces of Wielkopolskie and Lodzkie to the north and Slaskie to the east, by the Czech Republic to ...
opossum: any of about 66 species of New World mammals constituting the family Didelphidae of the superorder Marsupialia. For ordinal relatives in American tropics, see rat opossum; for Australasian marsupials called ...
opossum shrimp: any member of the crustacean order Mysidacea. Most of the 450 known species live in the sea; a few live in brackish water; and fewer still live in fresh water. ...
Oppen, George: American poet and political activist, one of the chief proponents of Objectivism, a variation on Imagism.
Oppenheim, E. Phillips: internationally popular British author of novels and short stories dealing with international espionage and intrigue.