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  • Oniyasha (Japanese dramatist)
    the greatest playwright and theorist of the Japanese nō theatre. He and his father, Kan’ami (1333–84), were the creators of the nō drama in its present form....
  • “Onkelos, Targum of” (biblical literature)
    ...of a written Targum, and therefore the final fixing of its text, belongs to the post-Talmudic period of the 5th century ad. The best known, most literal, and possibly the earliest Targum is the Targum of Onkelos on the Pentateuch, which appeared in its final revision in the 3rd century ad. Other Targums include the Targum of Pseudo-Jonathan, the Samaritan Targum, and...
  • “Onkl Mozes” (work by Asch)
    ...in 1910 but banned elsewhere. Asch visited the United States in 1910, returned there in 1914, and became a naturalized U.S. citizen in 1920. To this period belong Onkl Mozes (1918; Uncle Moses), Khayim Lederers tsurikkumen (1927; Chaim Lederer’s Return), and Toyt urteyl (1926; “Death Sentence”; Eng. trans. Judge Not—). These....
  • Onkos (costume)
    ...accorded to each character. He enumerates 30 masks used in tragedy and lists the characteristics of the comedy series, which are particularly exaggerated and grotesque. The onkos, a high ornate headdress, crowned some masks, adding height and thus importance to the wearer....
  • Onley, Toni (Canadian artist)
    Canadian painter (b. Nov. 20, 1928, Douglas, Isle of Man—d. Feb. 29, 2004, Maple Ridge, B.C.), was internationally known for his evocative Impressionist paintings of western and northern Canada and was famous for his 1983 threat to burn his entire inventory in an ultimately successful fight against Revenue Canada. Onley, who loved to fly his plane into the backcountry to paint, died when hi...
  • online auction
    Internet auctions, first introduced in 1995, have transformed the way many goods are sold. On Web sites such as eBay, rare or obscure items, as well as ordinary or mundane ones, are auctioned to bidders who may be located anywhere in the world. The number of competing bids displayed on the site indicates the level of demand for an item. Bidding in most online auctions ends at a scheduled time,......
  • online community
    The global popularization of the Internet was accompanied by a boom in electronic commerce, or e-commerce. British computer scientist Tim Berners-Lee, creator of the World Wide Web, soon argued that this focus on commerce was misplaced, as it assumed that Internet users remained primarily consumers of information and content developed by others for online distribution. He argued that the core......
  • online encyclopaedia (electronics)
    In 1983 the Academic American Encyclopedia became the first encyclopaedia to be presented to a mass market online by the licensing of its text to commercial data networks, which eventually included CompuServe and Prodigy Information Service. Nine years later Compton’s Encyclopedia licensed its text to America Online, another commercial information provider. In 1994...
  • online gaming (computer science)
    ...or even one-to-many communication is only the most elementary form of Internet social life. The very nature of the Internet makes spatial distances largely irrelevant for social interactions. Online gaming has moved from simply playing a game with friends to a rather complex form of social life in which the game’s virtual reality spills over into the physical world. The case of ......
  • online publishing
    Nearly all the world’s major newspapers began publishing online editions of their newspapers in the early 21st century. Although some newspaper publishers charged their readers for this access, many made their Web editions available for free, based on the expectation that advertising revenue, combined with lower printing and distribution costs, could make up for lost subscription fees....
  • online system (communications)
    any electronic interactive system that delivers information to users via telephone lines to personal computers (PCs) or via cables to terminals. Such a service provides information, usually in text form, about news, education, business, entertainment, shopping, and more. Some also provide message services and graphic and audio information. The term videotex w...
  • oNLine System (computer science)
    ...described many of the uses computers would have, such as word processing. In 1968, as a researcher at the Stanford Research Institute (SRI), Engelbart gave a remarkable demonstration of the “NLS” (oNLine System), which featured a keyboard and a mouse, a device he had invented that was used to select commands from a menu of choices shown on a......
  • Only Begotten Son, The (song)
    ...year. In modern practice most troparia are recited, although a few are still chanted. One that has retained a special place in the liturgy is “Ho Monogenēs” (“The Only Begotten Son”), believed to have been written by the Byzantine emperor Justinian I (reigned 527–565). See also Byzantine chant....
  • Only Love Can Break a Heart (song)
    ...David’s The Man Who Shot Liberty Valance; the latter rendition rose to number four in the American pop charts in 1962. Pitney also reached the Top Ten with Only Love Can Break a Heart (1962), It Hurts to Be in Love (1964), and I’m Gonna Be Strong (1964). As his career waned in the U...
  • Only Son, The (novel by Munonye)
    Munonye’s first novel, The Only Son (1966), describes the separation of a mother from her son because of religious differences. Obi (1969), a sequel to The Only Son, broadens the theme to an extended family and the clash between African traditions and European beliefs. In both books the family emerges as a source of strength in times of turmoil. Munonye’s later n...
  • Only When I Larf (work by Deighton)
    ...his blend of espionage and suspense. Like The Ipcress File, these novels centre on an unnamed hero and show Deighton’s craftsmanship, crisp prose style, and mastery of plot. In Only When I Larf (1968), Deighton moved from the subject of spies to confidence tricksters. In the suspense novel Bomber (1970), he treated a misdirected bombing mission of World War II....
  • Onmun (Korean alphabet)
    alphabetic system used for writing the Korean language. The system, known as Chosŏn muntcha in North Korea, consists of 24 letters, including 14 consonant and 10 vowel symbols. The consonant symbols are formed with curved or angled lines; vowel symbols are composed of vertical or horizontal straight lines together with short lines on either side of the main line....
  • Onn bin Jaʾafar, Dato (Malaysian politician)
    Malayan political figure who played a leading role in the Merdeka (independence) movement and the establishment of the Federation of Malaya, forerunner of the present country of Malaysia....
  • Onna daigaku (work by Kaibara)
    ...Kaibara tells parents to severely discipline their children, who must blindly and respectfully accept all that parents tell them, whether it is right or wrong. To Kaibara is usually attributed Onna daigaku (“The Great Learning for Women”), long considered the most important ethical text for women in Japan, which advocates women’s obedience to their parents, parents-i...
  • onna Kabuki (Japanese arts)
    ...normally had the patronage of the nobility; but their appeal was directed toward ordinary townspeople, and the themes of their dramas and dances were taken from everyday life. The popularity of onna (“women’s”) Kabuki remained high until it was officially banned in 1629 by the shogun (military ruler), who thought that the prostitution practiced by many of the dancers...
  • onna-de (Japanese script)
    Naturally, it was unsuitable for Japan to adopt an entire foreign language like Chinese, and Japanese thinkers began to devise a new, native script known as hiragana, which was often referred to as “women’s hand,” or onna-de in Japanese. It was used particularly in the writing of Japanese poetry ...
  • onnade (Japanese script)
    Naturally, it was unsuitable for Japan to adopt an entire foreign language like Chinese, and Japanese thinkers began to devise a new, native script known as hiragana, which was often referred to as “women’s hand,” or onna-de in Japanese. It was used particularly in the writing of Japanese poetry ...
  • onnagata (Japanese arts)
    ...kyōgen (sketches that provide comic interludes during Noh performances). During this period a special group of actors, called onnagata, emerged to play the female roles; these actors often became the most popular of their day....
  • “Onnamen” (work by Enchi)
    ...but freed her from the dreariness of her own life and enabled her to embark on a literary career. Onnamen (1958; “Female Mask”; Eng. trans. Masks) depicts, by invoking the various female masks used in the Noh dramas, different unhappy women. Enchi’s early background in Japanese classical literature is revealed in her allusio...
  • “Onnazaka” (novel by Enchi)
    ...of Hunger”) earned Enchi her first public acclaim. More success came with the novel Onnazaka (1957; “Female Slope”; Eng. trans. The Waiting Years), an account of a woman of the Meiji period (1868–1912) who defers to all her husband’s wishes, even choosing mistresses for him. The novel, based in part on the life...
  • Onnes, Heike Kamerlingh (Dutch physicist)
    Dutch winner of the Nobel Prize for Physics in 1913 for his work on low-temperature physics and his production of liquid helium. He discovered superconductivity, the almost total lack of electrical resistance in certain materials when cooled to a temperature near absolute zero....
  • Ono no Imoko (Japanese artist)
    ...century by Chinese Buddhist missionaries who had formalized the ritual of offering flowers to the Buddha. The first school of flower arranging in Japan, Ikenobō (q.v.), was founded by Ono no Imoko in the early 7th century. Based on a harmony of simple linear construction and an appreciation of the subtle beauty of flowers and natural material, ikebana has separated into several......
  • Ono Tōfū (Japanese calligrapher)
    Japanese calligrapher known as one of the Sanseki (“Three Brush Traces”), in effect the first calligraphers of the age. The others were Fujiwara Yukinari and Fujiwara Sukemasa, and the three perfected the style of writing called jōdai-yō (“ancient style”)....
  • Ono, Yoko (American artist)
    ...the Beatles, part of whose power lay in the multiplicity and collectivity they projected. But as Lennon began to withdraw from the Beatles, a process accelerated as of 1968 by his relationship with Ono, his declarative side took over. This dovetailed with the artistic ideas of Ono, a well-born Japanese avant-gardist seven years his senior. Lennon was first fascinated and then influenced by her....
  • Onoclea sensibilis (plant)
    ...one individual, or from different individuals. In the bracken fern (Pteridium aquilinum), although the gametophytes are bisexual, self-incompatability factors reduce self-fertilization. In Onoclea sensiblis, the gametophytes are unisexual in early development, thus favouring cross-fertilization; but, later, the gametophytes become bisexual so that, if cross-fertilization fails, th...
  • Onoe Baiko VII (Japanese actor)
    (SEIZO TERASHIMA), Japanese Kabuki actor (b. Aug. 31, 1915, Tokyo, Japan--d. March 24, 1995, Tokyo), was revered as the country’s leading postwar onnagata (female impersonator) and was designated a Living National Treasure in 1968. Baiko captivated audiences with his exquisite style, sensitive yet riveting portrayals, and masterful interpretations. In keeping with the ancient art of ...
  • Onoe Kikugorō V (Japanese actor)
    As they always had, kabuki writers and actors of the Meiji period tried to place current events on the stage. Thus, the actor Onoe Kikugorō V began acting in a series of contemporary plays, dressed in daily kimono or Western clothes and with his hair cut Western fashion (the origin of zangirimono, or the so-called “cropped-hair plays”), in the late 19th century. Western...
  • Onoe Shōroku II (Japanese actor)
    Japanese kabuki actor, one of the foremost interpreters of the classical kabuki plays, who specialized in female roles (all kabuki players are male)....
  • Onomarchus (Phocian leader)
    ...The Phocians seized the temple treasure in 356 and recruited a mercenary force of such size and efficiency that the Thebans could not defeat them. The Phocian leaders were Philomelus, followed by Onomarchus, Phayllus, and finally Phalaecus. The actual declaration of the Sacred War was delayed until 355, partly because it was only in that year that the relative impotence of one of Phocis’...
  • Onomasticon (work by Pollux)
    ...spectators. Detailed literary accounts of theatre and scenery in ancient Greece can be found in De architectura libri decem, by the 1st-century-bc Roman writer Vitruvius, and in the Onomasticon, of the 2nd century ad, by the Greek scholar Julius Pollux. As these treatises appeared several hundred years after classical theatre, however, the accuracy of t...
  • onomastics (linguistics)
    The science that studies names in all their aspects is called onomastics (or onomatology—an obsolete word). The subject of this science is broad because almost everything can have a name and because the study of names theoretically encompasses all languages, all geographical and cultural regions, and all historical epochs. For practical purposes, some divisions of the subject are......
  • Onomatologos ē pinax tōn en paideia onomastōn (work by Hesychius of Miletus)
    Hesychius also wrote a history of the emperor Justin I (518–527) and of the early years of Justinian I, but the work is lost. His Onomatologos ē pinax tōn en paideia onomastōn (“Nomenclature, or Index of Famous Persons in Learning”) is significant for its biographical notices of notable Greek writers. In it the authors were classified as poets,......
  • onomatopoeia (linguistics)
    the naming of a thing or action by a vocal imitation of the sound associated with it (such as buzz or hiss). Onomatopoeia may also refer to the use of words whose sound suggests the sense. This occurs frequently in poetry, where a line of verse can express a characteristic of the thing being portrayed. In the following lines from Sylvia Plath’s poem “Daddy,” the ...
  • Onomichi (Japan)
    city, Hiroshima ken (prefecture), Honshu, Japan, facing the Inland Sea. The city’s port opened in 1168 and served for about 500 years as a rice shipment centre and port of call for trade with China. The port’s commercial significance declined somewhat during the Tokugawa era (1603–1867) but has since revived. Onomichi now offers steamship services to ...
  • Onon River (river, Mongolia)
    ...Orhon, drains northward across the Russian border and into Lake Baikal; the Mongolian portion of the Selenge valley is in the north-central portion of the country. Mongolia’s other major rivers, the Onon and the Kerulen, run latitudinally across the eastern part of the country. The largest rivers draining into the interior are the Hovd (Kobdo), which rises from the glaciers of the Mongol...
  • Onondaga (county, New York, United States)
    county, central New York state, U.S., bounded by the Oswego and Oneida rivers to the north, Oneida Lake to the northeast, De Ruyter Reservoir to the southeast, Skaneateles Lake to the southwest, and Cross Lake to the west. It comprises a marshy lowland in the north and a hilly plateau region in the south. Other waterways include Onondaga and Otisco lakes and the Seneca River. Ca...
  • Onondaga (people)
    tribe of Iroquoian-speaking North American Indians who lived in what is now the U.S. state of New York. The Onondaga traditionally inhabited villages of wood and bark longhouses occupied by related families. They moved these houses periodically to plant new fields, to seek fresh supplies of firewood, and to be nearer fish and game. They grew corn (maize), beans, squash, sunflowers, and tobacco. A ...
  • ONR (political party, Poland)
    ...Camp of National Unity. The peasant parties (now united); the increasingly chauvinist National Party (as the National Democrats were by then known), with its fascist splinter party, the National Radical Camp; and the socialists all opposed the regime and achieved success in municipal elections. Socioeconomic tension was translated into peasant strikes in the countryside and riots in......
  • Onsager, Lars (American chemist)
    Norwegian-born American chemist whose development of a general theory of irreversible chemical processes gained him the 1968 Nobel Prize for Chemistry....
  • Onslow Courthouse (North Carolina, United States)
    city, seat (1755) of Onslow county, southeastern North Carolina, U.S. It lies along the New River at the head of its estuary, about 50 miles (80 km) northeast of Wilmington. Originally settled as Wantland’s Ferry (c. 1757), its name was changed to Onslow Courthouse and then Jacksonville in 1842 to honour President Andrew Jackson. It r...
  • Onslow Ford, Gordon (British-American painter)
    British-born American painter (b. Dec. 26, 1912, Wendover, Buckinghamshire, Eng.—d. Nov. 9, 2003, Inverness, Calif.), was associated with the Paris Surrealists but came to be interested in spontaneous creation and such metaphysical concerns as psychologist Carl Jung’s idea of the collective unconscious. The grandson of a sculptor, Onslow Ford served in the Royal Navy (1927–37)...
  • Ontake, Mount (mountain, Japan)
    mountain, rising to an elevation of 10,049 feet (3,063 m) on the boundary of Gifu and Nagano prefectures, central Honshu, Japan. A compound volcano with a heavy snow mantle in winter, it is second only to Mount Fuji in elevation and popular esteem. Mount Ontake is an object of worship for pilgrims who climb it each year....
  • Ontake-san (mountain, Japan)
    mountain, rising to an elevation of 10,049 feet (3,063 m) on the boundary of Gifu and Nagano prefectures, central Honshu, Japan. A compound volcano with a heavy snow mantle in winter, it is second only to Mount Fuji in elevation and popular esteem. Mount Ontake is an object of worship for pilgrims who climb it each year....
  • Ontario (province, Canada)
    second largest province of Canada in area, after Quebec. It occupies the strip of the Canadian mainland lying between Hudson and James bays to the north and the St. Lawrence River–Great Lakes chain to the south. It is bordered to the east by the province of Quebec, to the south ...
  • Ontario (California, United States)
    city, San Bernardino county, southern California, U.S. It is situated in the Riverside–San Bernardino portion of the consolidated Los Angeles metropolitan area on the site of the Spanish colonial Rancho Cucamonga. Named for the province of Ontario in Canada, it was settled in 1882 by George and William Chaffey, who irrigated the land ...
  • Ontario (county, New York, United States)
    county, western New York state, U.S., located southeast of Rochester and bounded by Seneca Lake to the east, Canandaigua Lake to the southeast, and Hemlock Lake and Honeoye Creek to the west. The northern part of the county comprises a lowland region, while the southern section contains more hills and larger stands of hardwood trees. Other bodies of water are Canadice and Honeoy...
  • Ontario (Oregon, United States)
    city, Malheur county, eastern Oregon, U.S. It lies at the juncture of the Snake and Malheur rivers, 60 miles (97 km) west of Boise, Idaho, on the historic Oregon Trail. A gateway to the Oregon cattle country, it grew after the building of the Union Pacific Railroad in 1884 and was named for the province of Ontario, Canada....
  • Ontario, flag of (Canadian provincial flag)
    ...
  • Ontario, Lake (lake, North America)
    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 is roughly elliptical; its major axis, 193 miles (311 km) long, lies nearly east to west, and its greatest width is 53 miles (85 km). The total area of the lake’s drainage basin is 24,720 square miles (64,025 square km), exclusive of the ...
  • Ontario Professional Hockey League (sports organization)
    ...Gibson, who imported Canadian players. In 1904 Gibson formed the first acknowledged professional league, the International Pro Hockey League. Canada accepted professional hockey in 1908 when the Ontario Professional Hockey League was formed. By that time Canada had become the centre of world hockey....
  • Ontario Provincial Museum (museum, Toronto, Ontario, Canada)
    ...well-known museums. In Canada the collection of the National Museum commenced in 1843 in Montreal as part of the Geological Survey, while the precursor of the Royal Ontario Museum in Toronto, the Ontario Provincial Museum, was founded in 1855. In Australia the National Museum of Victoria was established at Melbourne in 1854; it was followed by the National Gallery of Victoria in 1861 and the......
  • Ontario Science Centre (museum, Toronto, Ontario, Canada)
    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 available to the public an aquarium, arboretum, outdoor exhibits, and a theatre....
  • ontogeny (biology)
    The processes of development are regulated in such a way that few malformed organisms are found. Those that do appear may, when properly studied, shed light on normal development. The science of teratology—a branch of morphology or embryology—is concerned with the study of these structural deviations from the normal, whether in animals or plants....
  • Ontogeny and Phylogeny (work by Gould)
    Apart from his technical research, Gould became widely known as a writer, polemicist, and popularizer of evolutionary theory. In his books Ontogeny and Phylogeny (1977), The Mismeasure of Man (1981), Time’s Arrow, Time’s Cycle (1987), and Wonderful Life (1989), he traced the course and...
  • Ontologia sive Metaphysica de Ente (work by Clauberg)
    ...Teutonum e Philosophiae (1663; “The Art of Teutonic Etymology”), Clauberg wrote lucid expositions of Descartes’s Meditations and Principia Philosophiae. In his Ontologia sive Metaphysica de Ente (1660; “Ontology or Metaphysics of Being”), Clauberg sought to reconcile Cartesian doctrines with the metaphysical positions of his pre-Car...
  • ontological argument (philosophy)
    The distinction between tautological and significant propositions figures importantly in the history of the philosophy of religion. In the so-called ontological argument for the existence of God, St. Anselm of Canterbury (1033/34–1109) attempted to derive the significant conclusion that God exists from the tautological premise that God is the only perfect being together with the premise......
  • ontological individualism (philosophy)
    ...any explanation of such a fact ultimately must appeal to, or be stated in terms of, facts about individuals—about their beliefs, desires, and actions. A closely related view, sometimes called ontological individualism, is the thesis that social or historical groups, processes, and events are nothing more than complexes of individuals and individual actions. Methodological individualism.....
  • ontological reductionism (philosophy)
    ...in many fields of philosophy, but especially in the philosophy of science, is reductionism. There are at least three distinct kinds of reductionism: ontological, methodological, and theoretical. Ontological reductionism is the metaphysical doctrine that entities of a certain kind are in reality collections or combinations of entities of a simpler or more basic kind. The pre-Socratic doctrine......
  • ontologism (philosophy)
    ...known in Italy, Gioberti introduced Kantian and post-Kantian metaphysics. His own theology, philosophy, and political views revolved around his concept of being, and his system is usually termed “ontologism.” He coined the term “palingenesis” to indicate the return of human concepts to the essential centre of being from which they become divorced. This reunion of the...
  • ontology (metaphysics)
    the philosophical study of being in general, or of what applies neutrally to everything that is real. It was called “first philosophy” by Aristotle in Book IV of his Metaphysics. The Latin term ontologia (“science of being”) was felicitously (and independently) invented ...
  • ontology (Lesniewski’s logic)
    ...distinctive and original contribution of Leśniewski consists in the construction of three interrelated logical systems, to which he gave the names, derived from the Greek, of protothetic, ontology, and mereology (q.v.). The logical basis of the whole theory, and hence its name (prōtos, “first”), is provided by protothetic, which is the most......
  • Ontong Java Atoll (atoll, Solomon Islands)
    atoll in the country of Solomon Islands, southwestern Pacific Ocean, 160 miles (257 km) north of Santa Isabel Island. A large coral formation measuring some 20 miles (32 km) by 50 miles (80 km), the atoll was visited by the Dutch navigator Abel Janszoon Tasman in 1643 and was renamed Lord Howe Islands by Capt. John Hunter of the British Navy in 1791. Passages through the encircl...
  • Onu (ancient city, Egypt)
    one of the most ancient Egyptian cities, and the seat of worship of the sun god, Re. It was the capital of the 15th nome of Lower Egypt, but Heliopolis was important as a religious rather than a political centre. Its great temple of Re was second in size only to that of Amon at Thebes, and its priesthood wielded great influence, particularly during the 5th dynasty, when the wors...
  • Onuba (Spain)
    city and port, capital of Huelva provincia (province), in the comunidad autónoma (autonomous community) of Andalusia, southwestern Spain. The city lies on the western shore of a peninsula formed by the estuaries of the Odiel and Tinto rivers, which empty i...
  • Onuphis (polychaete genus)
    ...many aciculae (needlelike structures); size, minute to 3 m; examples of genera: Palola (palolo), Eunice, Stauronereis, Lumbineris, Onuphis.Order OrbiniidaSedentary; head pointed or rounded without appendages; proboscis eversible and unarmed; body divid...
  • Onverwacht Series (geology)
    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 in the Komati valley in the eastern Transvaal region, South Africa, where Onverwacht rocks consist of dark, andesitic lavas, dolomitic limestones, cherts, and jaspers, as well as serpentines, gabbros, and peridotites. ...
  • Onychogalea (marsupial)
    ...prettily coloured in shades of brown and gray and are distinguished by stripes, patches, or other markings. They are extremely agile on rocky terrain. The three species of nail-tailed wallabies (Onychogalea; see photograph) are named for a horny growth on the tail tip. They are handsomely striped at the shoulder. Because they rotate their forelimbs while hopping, they are often called......
  • Onychomys (rodent)
    any of three species of terrestrial, nocturnal, insectivorous and carnivorous mice that are physiologically adapted to semiarid and arid habitats in the open country of western North America. The northern grasshopper mouse (Onychomys leucogaster) lives in grassland and shrub steppes from central Canada southward through the Great Plains and Great Basin to northern Mexico. The southe...
  • Onychomys arenicola (rodent)
    ...the Great Plains and Great Basin to northern Mexico. The southern grasshopper mouse (O. torridus) is found from southern California, Nevada, and Utah southward to northeastern Mexico. Mearns’ grasshopper mouse (O. arenicola) ranges from the southwestern United States to central Mexico. The last two species prefer warm, very arid, scrubby desert habitats. All...
  • Onychomys leucogaster (rodent)
    any of three species of terrestrial, nocturnal, insectivorous and carnivorous mice that are physiologically adapted to semiarid and arid habitats in the open country of western North America. The northern grasshopper mouse (Onychomys leucogaster) lives in grassland and shrub steppes from central Canada southward through the Great Plains and Great Basin to northern Mexico. The......
  • Onychomys torridus (rodent)
    ...northern grasshopper mouse (Onychomys leucogaster) lives in grassland and shrub steppes from central Canada southward through the Great Plains and Great Basin to northern Mexico. The southern grasshopper mouse (O. torridus) is found from southern California, Nevada, and Utah southward to northeastern Mexico. Mearns’ grasshopper mouse (O. arenicola...
  • Onychophora (invertebrate phylum)
    any of about 70 wormlike species of ancient, terrestrial invertebrates with short, thick legs and a dry, velveteen body. Onychophorans range in size from 14 to 150 mm (about 0.6 to 6 inches) and are found in rainforests. Unable to control water loss, they cannot tolerate dry habitats....
  • onychophoran (invertebrate phylum)
    any of about 70 wormlike species of ancient, terrestrial invertebrates with short, thick legs and a dry, velveteen body. Onychophorans range in size from 14 to 150 mm (about 0.6 to 6 inches) and are found in rainforests. Unable to control water loss, they cannot tolerate dry habitats....
  • onychophore (invertebrate phylum)
    any of about 70 wormlike species of ancient, terrestrial invertebrates with short, thick legs and a dry, velveteen body. Onychophorans range in size from 14 to 150 mm (about 0.6 to 6 inches) and are found in rainforests. Unable to control water loss, they cannot tolerate dry habitats....
  • Onychopoda (crustacean)
    ...Anchistropus, parasitic on Hydra; no larval stages; resting eggs enclosed in a special case or ephippium; worldwide in fresh water.Infraorder Onychopoda Short-bodied forms with carapace reduced to a dorsal brood pouch; 4 pairs of trunk limbs, which only grasp prey; single large median eye with many visual el...
  • Onychoteuthis (squid genus)
    ...rapid undulation of the outer edges of the fins. Movement through the water is aided by lateral expansions (swimming keels) on the outer surface of the third pair of arms. Some squids (Onychoteuthis, Thysanoteuthis) are able to “fly” for several hundred feet, driven into the air by powerful thrusts from their jets and gliding on their expanded fins....
  • Onygenales (order of fungi)
    ...examples of genera include Eurotium, Penicillium, Talaromyces, Elaphomyces, Trichocoma, and Byssochlamys.Order OnygenalesForms lichens; asci are formed in a mazaedium (a fruiting body consisting of a powdery mass of free spores interspersed with sterile threads, enclosed in a peri...
  • onyx (mineral)
    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 a colour contrast between the design and the background. Other varieties include carnelian onyx, with white and red bands, and sardonyx, with white and brown bands. The chief localities of onyx are India and South Ameri...
  • onyx marble (rock)
    The so-called onyx marbles consist of concentric zones of calcite or aragonite deposited from cold-water solutions in caves and crevices and around the exits of springs. They are, in the strict sense, neither marble nor onyx, for true onyx is a banded chalcedony composed largely of silicon dioxide. Onyx marble was the “alabaster” of the ancients, but alabaster is now defined as......
  • Onyx River (river, Antarctica)
    ...everywhere in Antarctica, and erosional effects of running water are relatively minor. Yet, on warm summer days, rare and short-lived streams of glacial meltwater do locally exist. The evanescent Onyx River, for example, flows from Lower Wright Glacier terminus to empty into the nondrained basin of Lake Vanda near McMurdo Sound. Glacially sculptured landforms now predominate, as they must......
  • Onze Lieve Vrouwkerk (church, Kortrijk, Belgium)
    The Church of Notre Dame (Onze Lieve Vrouwkerk; 1191–1211), with the attached chapel of the counts of Flanders (1374), contains Anthony Van Dyck’s “Elevation of the Cross” (1631) and a 14th-century statue of St. Catherine. Other historic landmarks in Kortrijk include the Broelbrug (bridge; c. 1400), with its two massive towers; the Gothic St. Martin’s Chur...
  • oocyst (biology)
    ...Temporary or long-lasting cysts may occur among other protist species as well. Many sporozoa and members of other totally parasitic phyla form a highly resistant stage—for example, the oocyst of the coccidians, which may survive for a long time in the fecal material of the host or in the soil. This cyst is the infective stage for the next host in the parasite’s life cycle....
  • oocyte (physiology)
    In the case of multicellular animals we find there are two kinds of sex cells: the female sex cell (ovum, or egg), derived from an oocyte (immature egg), and the male sex cell (spermatozoon or sperm), derived from a spermatocyte. Eggs are produced in ovaries; sperm, in testes. Both the egg and the sperm contribute to the development of the new individual; each providing one set of genes,......
  • Oodnadatta (South Australia, Australia)
    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 the railway was extended to Alice Springs some 280 miles [450 km] north-northwest in 1929), and it was the starting point for camel caravans laden with supplies for the remote communitie...
  • oogamy (genetics)
    ...type (heterogamy), as with many green algae of the genus Chlamydomonas. Gametes of animals, some algae and fungi, and all higher plants exhibit an advanced form of heterogamy called oogamy. In oogamy, one of the gametes is small and motile (the sperm), and the other is large and nonmotile (the egg). See also egg; sperm....
  • oogenesis (physiology)
    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 the female that carries it is even born; 8 to 20 weeks after the fetus has started to grow, cells that are to become mature ova have been multiplying, and by the time tha...
  • oogonia (plant anatomy)
    the female reproductive organ in ferns and mosses. An archegonium also occurs in some gymnosperms, e.g., cycads and conifers. A flask-shaped structure, it consists of a neck, with one or more layers of cells, and a swollen base—the venter—which contains the egg. Neck-canal cells, located above the egg, disappear as the ...
  • ooid (geology)
    ...nondetrital fragments (allochems) that undergo a brief history of transport and abrasion prior to deposition as nonterrigenous clasts. Examples are calcareous or siliceous shell fragments and oöids, which are concentrically layered spherical grains of calcium carbonate. Orthochemical sedimentary rocks, on the other hand, consist of dissolved constituents that are directly......
  • Ōoka Makoto (Japanese poet and literary critic)
    prolific Japanese poet and literary critic who was largely responsible for bringing contemporary Japanese poetry to the attention of the Western world....
  • Ōoka Shōhei (Japanese author)
    Japanese novelist famous for his depiction of the fate of Japanese soldiers during World War II....
  • Ōoka Tadasuke (Japanese jurist)
    highly respected Japanese judge of the Tokugawa period (1603–1867)....
  • ookinete (biology)
    ...into a sexual stage known as a gametocyte. These will mate only when they enter the gut of another mosquito that bites the infected person. Mating between gametocytes produces embryonic forms called ookinetes; these embed themselves in the mosquito’s gut, where they mature after 9 to 14 days into oocysts, which in turn break open and release thousands of sporozoites that migrate to the i...
  • oölite (rock)
    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 oxide. Oölite diameters range from 0.25 to 2 mm (0.01 to 0.08 inch), with most being in the 0.5- to 1-millimetre range; oölitic bodies with diameters greater than 2 mm are called ...
  • oolitic iron deposit
    ...type of chemically precipitated marine iron deposit. Containing pinhead-sized ooliths (small, rounded, accretionary masses formed by repeated deposition of thin layers of an iron mineral), these oolitic iron deposits have been largely supplanted in importance by BIFs, but they once formed the backbone of the iron and steel industries in western Europe and North America. European oolitic iron......
  • oolong tea (beverage)
    After a brief withering stage, the leaf is lightly rolled by hand until it becomes red and fragrant. For oolong it is then fermented for about one-half, and for pouchong for one-quarter, of the time allowed for black tea. Fermentation is stopped by heating in iron pans, and the leaf is subjected to more rolling and heating until it is dried....
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