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Encyclopedias since 1768

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Uman ... undersea exploration

Uman: city, Cherkasy oblast (province), central Ukraine, on the Umanka River. It dates from the Middle Ages and was incorporated in 1795. Uman is an industrial centre specializing in scientific instruments, with some engineering, food, and building-materials industries. It has teacher-training ...
umangite: a copper selenide (Cu₃Se₂) occurring only in small grains or fine granular aggregates with other copper minerals of the sulfide group. The mineral is bluish black with a reddish tint. Deposits of the mineral are found in the Sierra de ...
Umar I: the second Muslim caliph (from 634), under whom Arab armies conquered Mesopotamia and Syria and began the conquest of Iran and Egypt.
Umar ibn Abi Rabi'ah: full name 'umar Ibn 'abd Allah Ibn Abi Rabi'ah Al-makhzumi one of the greatest early Arabic poets.
Umar II: pious and respected caliph who attempted to preserve the integrity of the Muslim Umayyad caliphate (661-750) by emphasizing religion and a return to the original principles of the Islamic faith.
Umar Tal: West African Tukulor leader who, after launching a jihad (holy war) in 1854, established a Muslim realm, the Tukulor empire, between the upper Senegal and Niger rivers (in what is now upper Guinea, eastern Senegal, and western and central Mali). ...
Umari, al-: in full Shihab Ad-din Ahmad Ibn Fadl Allah Al-'umari scholar and writer whose works on the administration of the Mamluk dominions of Egypt and Syria became standard sources for Mamluk history.
Umayyad Dynasty: first great Muslim dynasty to rule the Empire of the Caliphate (AD 661-750), sometimes referred to as the Arab kingdom (reflecting traditional Muslim disapproval of the secular nature of the Umayyad state). The Umayyads, headed by Abu Sufyan, were a ...
Umberto I: duke of Savoy and king of Italy who led his country out of its isolation and into the Triple Alliance with Austria-Hungary and Germany. He supported nationalistic and imperialistic policies that led to disaster for Italy and helped create the ...
Umberto II: prince of Savoy and briefly king of Italy in 1946 until he was forced to abdicate after a republican form of government was approved in a general referendum.
umbilical cord: narrow cord of tissue that connects a developing embryo, or fetus, with the placenta (the extra-embryonic tissues responsible for providing nourishment and other life-sustaining functions). In the human fetus, the umbilical cord arises at the belly and by the time ...
umbra: that part of a shadow area over which all light from a given source is excluded. The shadow from a point source of illumination is essentially all umbra, but that from a source of some size (as from the Sun) ...
umbrella: a portable, hand-held device that is used for protection against rain and sunlight. The modern umbrella consists of a circular fabric or plastic screen stretched over hinged ribs that radiate from a central pole. The hinged ribs permit the screen ...
umbrella pine: (Sciadopitys verticillata), coniferous evergreen tree native to Japan, the only member of the genus Sciadopitys of the deciduous cypress family (Taxodiaceae). Although slow growing, it may reach a height of 36 m (116 feet), with a trunk diameter of 1.2 ...
umbrella plant: any of several unrelated but similarly leaved plants. Cyperus alternifolius (family Cyperaceae), also called umbrella palm and umbrella sedge, is widely cultivated in water gardens and as a potted plant. It grows up to 1 m (3 feet) high. Native ...
umbrellabird: any of three species of cotingas (family Cotingidae, order Passeriformes) of tropical American forests. They are notable for their unique, umbrella-like crest and for the pendant suspended from the throat, which is an inflatable wattle. When displaying, the male spreads ...
Umbri: ancient pre-Etruscan people who gradually concentrated in Umbria (in central Italy) in response to Etruscan and Gallic pressure. By about 400 BC the inhabitants of this area spoke an Indo-European dialect (Umbrian). The Umbri never fought any important wars against ...
Umbria: region, central Italy, including the provinces of Perugia and Terni, with an area of 3,265 square miles (8,456 square km). It lies roughly equidistant between Rome (south) and Florence (north). The modern region takes its name from the Umbria of ...
Umbrian language: one of the ancient Italic languages closely related to Oscan and Volscian and more distantly related to Latin and Faliscan. Umbrian was spoken in central Italy, probably only in the area of the Tiber River valley in the last few ...
Umbriel: one of the major satellites of the planet Uranus. It orbits the planet at a distance of 266,300 km (165,110 miles). Umbriel has an orbital period of 4.144 days. Its discovery is usually attributed to William Lassell in 1851, but ...
Umbrisol: one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). Umbrisols are characterized by a surface layer that is rich in humus but not in calcium available to plants, owing to high rainfall ...
Umea: town and capital of Vasterbotten lan (county), northeastern Sweden. It lies on the left bank of the Umea River near the Gulf of Bothnia. It has long been an educational and cultural centre for northern Sweden. In 1622 it was ...
Umehara Ryuzaburo: Western-style Japanese painter whose vibrant colours, dynamic brushstrokes, and liberated spirit had a strong impact on young Japanese painters.
Umfolozi Game Reserve: wild animal sanctuary in northern KwaZulu/Natal province, South Africa. The reserve lies southwest of the Hluhluwe Game Reserve, about 35 miles (56 km) inland from the Indian Ocean. It was established in 1897 and has an area of 185 square ...
umiak: boat used by the Greenland and later by the Alaskan Eskimos for transport. It was called the woman's boat, as opposed to the kayak, the men's hunting and fishing boat.
Umlazi: urban area, southeastern KwaZulu-Natal province, South Africa. It lies along the south bank of the Mlazi (Umlazi) River and adjoins the city of Durban on the southwest. The present site of Umlazi was occupied by American missionaries in 1836, but ...
Umm al-Qaywayn: constituent emirate of the United Arab Emirates, on the Arabian Peninsula facing the Persian Gulf. The second smallest in area and the least populous of the federation's seven emirates, Umm al-Qaywayn is roughly triangular in shape and is bounded by ...
Umm Kulthum: Egyptian singer, who mesmerized Arab audiences from the Persian Gulf to Morocco for half a century. She was one of the most famous Arab singers and public personalities in the 20th century.
Umniati River: river, tributary of the Zambezi River in north-central Zimbabwe. It has its source in the Daramumbe Range on the main watershed north of Chivhu. Flowing northwest for 325 miles (520 km), the Umniati joins the Zambezi River near the Kariba ...
umrah: the "minor pilgrimage" undertaken by Muslims whenever they enter Mecca. It is also meritorious, though optional, for Muslims residing in Mecca. Its similarity to the major and obligatory Islamic pilgrimage (hajj) made some fusion of the two natural, though pilgrims ...
Umtata: town, Eastern Cape province, South Africa. It was the capital of Transkei, a nominally independent but not internationally recognized southern African republic that was reincorporated into South Africa in 1994. Located on the Umtata ("The Taker") River (so named because ...
Umuahia: town, capital of Abia state, southern Nigeria. It lies along the railroad from Port Harcourt to Enugu. It is an agricultural market centre and (since 1916) collecting point on the railway for the crops of the surrounding region: yams, cassava, ...
Umvukwe Range: mountain range in northern Zimbabwe, extending about 100 miles (160 km) north from the Hunyani River and rising to a high point of 5,748 feet (1,752 m). The range forms the northern section of an enormous tabular block of igneous ...
Una: city, southwestern Himachal Pradesh state, northern India. It lies along the Soan River at an elevation of 1,815 feet (550 m), about 60 miles (95 km) northwest of Simla, the state capital. Formerly an important commercial centre, it declined after ...
Una, The: American publication, founded by Paulina W. Davis in 1853, that was widely recognized as the first periodical of the women's rights movement. Though several similar journals had appeared the previous year, The Una was the first to ...
Unaka Mountains: segments of the Blue Ridge and Appalachian mountain systems in the southeastern United States. They extend from southwestern Virginia along the Tennessee-North Carolina border into northern Georgia. The main ridges average 5,000 feet (1,500 m), rising in the Great Smoky ...
Unamuno, Miguel de: educator, philosopher, and author whose essays had considerable influence in early 20th-century Spain.
Unanimism: French literary movement based on the psychological concept of group consciousness and collective emotion and the need for the poet to merge with this transcendent consciousness. Founded by Jules Romains about 1908, Unanimism particularly influenced some members of the Abbaye ...
Unas: last king of the 5th dynasty (c. 2465-c. 2325 BC) in Egypt, the first pharaoh to inscribe the interior of his pyramid with religious and magical texts known as Pyramid Texts. According to later king lists, Unas was the last ...
unau: either of two species of tree-dwelling mammals also known as two-toed sloths. See sloth.
uncertainty principle: statement, articulated (1927) by the German physicist Werner Heisenberg, that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory. The very concepts of exact position and exact velocity together, ...
uncial: in calligraphy, ancient majuscular book hand characterized by simple, rounded strokes. It apparently originated in the 2nd century AD when the codex form of book developed along with the growing use of parchment and vellum as writing surfaces. Unlike its ...
Uncle Sam: popular U.S. symbol usually associated with a cartoon figure having long white hair and chin whiskers and dressed in a swallow-tailed coat, vest, tall hat, and striped trousers. His appearance is derived from two earlier symbolic figures in American folklore-Brother ...
unconscious: the complex of mental activities within an individual that proceed without his awareness. Sigmund Freud, the founder of psychoanalysis, stated that such unconscious processes may affect a person's behaviour even though he cannot report on them. Freud and his followers ...
Undenominational Fellowship of Christian Churches and Churches of Christ: autonomous Protestant churches in the United States that were formerly associated primarily with the Disciples of Christ. These churches refused to become part of the restructured Christian Church (Disciples of Christ) in 1968 because they feared that the development of ...
underground film: motion picture made and distributed outside the commercial film industry, usually as an artistic expression of its maker, who often acts as its producer, director, writer, photographer, and editor. Underground films usually display greater freedom in form, technique, and content ...
Underground Railroad: in the United States, a system existing in the Northern states before the Civil War by which escaped slaves from the South were secretly helped by sympathetic Northerners, in defiance of the Fugitive Slave Acts (q.v.), to reach places of ...
Underhill, Evelyn: English mystical poet and author of such works as Mysticism (1911), The Mystic Way (1913), and Worship (1936), which helped establish mystical theology as a respectable discipline among contemporary intellectuals.
Underhill, John: British-American colonial military officer, privateer, and magistrate.
undersea cable: assembly of conductors enclosed by an insulating sheath and laid on the ocean floor for the transmission of messages. Undersea cables for transmitting telegraph signals antedated the invention of the telephone; the first undersea telegraph cable was laid in 1850 ...
undersea exploration: the investigation and description of the ocean waters and the seafloor and of the Earth beneath.