Trans-Siberian Railroad
Trans-Siberian Railroad, railroad in Russia, the longest in the world, stretching 5,787 mi (9,313 km) from Moscow to Vladivostock on the Sea of Japan.
21st Century Webster's Family Encyclopedia - Transcendentalism to United Church of Christ
Transcendentalism
Transcendentalism, philosophical and literary movement that flourished in New England c. 1835–60.
Transcontinental treaty
Transcontinental treaty See: Adams-Onís Treaty.
Transducer
Transducer, device for converting an input of energy or information of one form into an output of another.
Transformer
Transformer, device for moving an alternating current by increasing or decreasing the voltage.
blood Transfusion
Transfusion, blood See: Blood transfusion.
Transistor
Transistor, device in electronic equipment thast regulates the flow of electricity in such equipment.
Transkei
Transkei, former independent homeland established by South Africa for the black Xhosa-speaking people.
Transmigration of the soul
Transmigration of the soul See: Reincarnation.
Transmission
Transmission, automobile part that transmits the power generated by the engine to a driving axle.
Transmutation of elements
Transmutation of elements, conversion of an atom of one element to an atom of another. Since atoms are identified by their atomic number (number of protons), any change in the number of protons will result in a different element. Atoms may change their number of protons by giving off or taking in atomic particles. Transmutation occurs naturally as a result of radioactive decay. Radioactive atoms a…
Transpiration
Transpiration, loss of water by evaporation from the aerial parts of plants.
Transplant
Transplant, organ removed from one person and surgically implanted in another to replace a lost or diseased organ. Autotransplantation is the moving of an organ from one place to another within a person, where the original site has been affected by local disease (e.g., skin grafting). Blood transfusions between those with compatible blood groups was the first practical form of transplant. In organ…
Department of Transportation
Transportation, Department of, executive department of the U.S. government responsible for the development and coordination of national transport policies and agencies.
Transsexualism
Transsexualism, condition in which a person has a psychological urge to belong to the opposite sex.
Transuranium elements
Transuranium elements, elements of atomic number above 92.
Transvaal
Transvaal, former province in the Republic of South Africa, between the Vaal and Limpopo rivers in the northeast.
Transylvania
Transylvania, province in central Romania near the Hungarian border, situated between the Transylvanian Alps and the Carpathian Mts.
Trappists
Trappists, members of the clan of the Reformed, or Strict, Observance, a Roman Catholic monastic order founded (1664) by Armand de Rancé, abbot of La Trappe in Normandy, France.
Travertine
Travertine, type of limestone that forms in dense layers.
Treason
Treason, behavior by a subject or citizen that could harm the sovereign or state.
Department of the Treasury
Treasury, Department of the, executive department of the U.S. government, established in 1789, responsible for federal taxes, customs, and expenditure.
Treaty
Treaty, agreement between states.
Treaty of 1
Treaty of 1783 See: Revolutionary War in America.
Tree
Tree, woody perennial plant with a well-defined main stem, or trunk, that either dominates the form throughout the life cycle (giving a pyramidal shape) or is dominant only in the early stages, later forking to form a number of equally important branches (giving a rounded or flattened form to the tree). The trunk of a tree consists almost wholly of thick-walled water-conducting cells (xylem) that …
Tree frog
Tree frog, or tree toad, one of several hundred types of frogs belonging to the family Hylidae, commonly found in North and South America.
Tree shrew
Tree shrew, small, squirrel-like arboreal insectivore (family Tupaiidae) with a pointed snout.
Tree toad
Tree toad See: Tree frog.
Trench mouth
Trench mouth, or Vincent's infection, disease of the mouth and throat, probably caused by bacteria, poor oral hygiene, and malnutrition.
Trent Affair
Trent Affair, naval incident in the U.S.
Council of Trent
Trent, Council of, series of 3 conferences held in Trent, Italy, by leaders of the Roman Catholic church in the mid-16th century. Convened by Pope Paul III in 1545 to counteract the Protestant Reformation in Europe, the council did much to define Catholic doctrine and bring about a Counter-Reformation. The first council, which lasted until 1547, established the Catholic church's sole right …
Trenton
Trenton (pop. 92,124), capital (since 1790) of New Jersey, situated at the head of navigation on the Delaware River, opposite Pennsylvania.
Battle of Trenton
Trenton, Battle of, American victory in the Revolutionary War, fought on Dec. 26, 1776.
Trephining
Trephining, surgical removal of a small, circular piece of skull.
George Macauley Trevelyan
Trevelyan, George Macauley (1876–1962), English historian who rejected the “scientific” approach to history in favor of a more humanistic and literary approach.
Triage
Triage (French, “sorting”), allocation of limited medical or food resources by selecting those in need who would most benefit in the long run.
Trial
Trial, method of settling disagreements of determining criminal guilt.
Trial by combat
Trial by combat, medieval method of settling disagreements.
Triangle
Triangle, three-sided polygon.
Treaty of Trianon
Trianon, Treaty of, World War I treaty that reduced Hungary's territory by almost two-thirds as punishment for its part in the war.
Triassic Period
Triassic Period, first period of the Mesozoic Era (c.225–190 million years ago).
Tribe
Tribe, people who live in a community in a particular area, sharing the same language, culture, and often kinship.
Trichina
Trichina, parasitic roundworm, belonging to the trichina family, that causes an infection known as trichinosis.
Trichinosis
Trichinosis See: Trichina.
Trier
Trier (pop. 93,500), city in southwestern Germany, on the Moselle River.
Trieste
Trieste (pop. 228,400), city-seaport in northeastern Italy at the head of the Adriatic Sea, with steel, oil, and shipbuilding industries.
Triggerfish
Triggerfish, fish belonging to the Balistidae family, found in tropical coastal waters.
Trigonometry
Trigonometry, branch of geometry that deals with the ratios of the sides and angles of triangles, particularly of right-angled triangles and the applications of these ratios. Plane trigonometry deals with these relationships mapped on a plane surface. The principle ratios, when considering angle A of right-triangle ABC whose sides opposite the angles A, B, and C respectively are a, b, and c, and w…
Trillium
Trillium, colorful wildflower (genus Trillium) of North American woodlands and eastern Asia.
Trilobite
Trilobite, extinct marine animal (phylum Arthropoda) from the Paleozoic Era (570–240 million years ago).
Trinidad and Tobago
Trinidad and Tobago, officially Republic of Trinidad and Tobago, independent republic in the West Indies, consisting of 2 separate islands in the Caribbean Sea north of Venezuela. The island of Trinidad is 1,864 sq mi (4,828 sq km) and Tobago is 116 sq mi (300 sq km). The capital is Port of Spain, on Trinidad. Trinidad is very fertile and mainly flat, rising to c.3,000 ft (914 m) above sea level i…
Trinitrotoluene
Trinitrotoluene See: TNT.
Trinity
Trinity, central doctrine of Christian theology, that there is one God who exists in three Persons and one Substance. The definition of the doctrine, implicit in the New Testament, by the early ecumenical councils (notably Nicaea and Constantinople) was the product of violent controversy with heresies like Arianism, Monophysitism, Nestorianism, and Monarchianism.It is classically summed up in the …
Triple Alliance
Triple Alliance, defense arrangement between Austria-Hungary, Germany, and Italy in the late 19th and early 20th centuries.
Triple Entente
Triple Entente, defense pact originally formed between France and Russia in 1890 to counterbalance the threat posed by the Triple Alliance—Germany, Austria-Hungary, and Italy—8 years earlier.
Tripoli
Tripoli (pop. 500,000), city located in northwestern Lebanon, second largest in the country.
Tripoli
Tripoli (pop. 990,700), capital and largest city of Libya, located in northwest Libya on an arm of the Mediterranean Sea.
Triticale
Triticale (genus Triticosecale), hybrid grain produced by crossbreeding wheat with rye.
Tritium
Tritium, hydrogen isotope that is 3 times heavier than ordinary hydrogen.
Triton
Triton, in Greek mythology, sea god with human head and chest and a fishlike tail.
Arch of Triumph
Triumph, Arch of See: Arc de Triomphe.
Trogon
Trogon, bird of the family Trogonidae.
Trojan horse
Trojan horse See: Trojan War.
Trojan War
Trojan War, conflict between Greece and Troy, made famous by Homer's Iliad.
Anthony Trollope
Trollope, Anthony (1815–82), English author.
Trombone
Trombone, musical instrument, one of the brass wind instruments.
Trona
Trona, carbonate mineral found in dry regions of the world or extracted from evaporated brine.
Tropic bird
Tropic bird, graceful seabird (genus Phaethon) with long, trailing tail feathers.
Tropic of Cancer
Tropic of Cancer, imaginary line of latitude showing the northernmost point on the earth at which the sun can appear directly overhead.
Tropic of Capricorn
Tropic of Capricorn, imaginary line of latitude showing the southernmost point on the earth at which the sun can appear directly overhead.
Tropical fish
Tropical fish, any of a variety of marine and freshwater fish native to the tropics, but particularly those valued for use in aquariums because they are ornamental, small, and able to reproduce quickly and easily.
Tropical rain forest
Tropical rain forest, regions of the world near the equator characterized by high levels of rainfall and humidity.
Tropics
Tropics, land and water 1,600 mi (2,570 km) north and south of the equator, as defined by the Tropic of Cancer (23°27' north latitude) and the Tropic of Capricorn (23°27' south latitude).
Tropism
Tropism, movement of a plant in response to external directional stimuli.
Troposphere
Troposphere, lowermost zone of the earth's atmosphere, extending from the earth's surface up to 5–6 mi (8–9 km) over the poles and 8–10 mi (12.8–16 km) over the equator.
Leon Trotsky
Trotsky, Leon (Lev Davidovic Bronstein; 1879–1940), Russian revolutionary Communist, a founder of the USSR. President of the Petrograd (Leningrad) soviet in the abortive 1905 revolution, he escaped from prison to France, Spain, and New York. In 1917 he returned, went over to Bolshevism, and led the Bolshevik seizure of power in the October Russian Revolution. As commissar of foreign affairs…
Troubadour
Troubadour, name for courtly poet-musicians of Provence, southern France (1100–1300).
Trout
Trout, any of several relatives of the salmon, native to the Northern Hemisphere.
Trout lily
Trout lily See: Dogtooth violet.
Troy
Troy, city of ancient northwestern Asia Minor, near the Dardanelles, described in Homer's Iliad and rediscovered by Heinrich Schliemann in 1870.
Trucial states
Trucial states See: United Arab Emirates.
Edward Livingston Trudeau
Trudeau, Edward Livingston (1848–1915), innovator of tuberculosis treatment in the United States.
Pierre Elliott Trudeau
Trudeau, Pierre Elliott (1919– ), Canadian prime minister (1968–79, 1980–84).
François Truffaut
Truffaut, François (1932–84), French film director and critic.
Truffle
Truffle, underground fungus (genus Tuber) that has long been regarded as a delicacy.
Rafael Leonidas Trujillo Molina
Trujillo Molina, Rafael Leonidas (1891–1961), Dominican Republic dictator (1930–61) and president (1930–38, 1942–52).
Truk Islands
Truk Islands, group of islands in the western Pacific, part of the Caroline Islands.
Truman Doctrine
Truman Doctrine, U.S. declaration (1947) stating the United States would “support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.” Aimed at halting communist expansion and aggression, the Truman Doctrine provided substantial aid to Greece and Turkey, helping those nations defeat communist guerrillas.
Harry S. Truman
Truman, Harry S. (1884–1972), 33rd president of the United States. The challenges of Truman's presidency, which began after the sudden death of Franklin D. Roosevelt, included the end of World War II, use of the first atom bomb, the Cold War, the Marshall Plan and NATO, the controversial McCarthy hearings, and the Korean War. Truman's poor eyesight kept him out of West Point, …
John Trumbull
Trumbull, John (1756–1843), U.S. painter.
Jonathan Trumbull
Trumbull, Jonathan (1710–85), governor of Connecticut (1769–84).
Lyman Trumbull
Trumbull, Lyman (1813–96), U.S. senator from Illinois who supported antislavery legislation.
Trumpet
Trumpet, musical instrument, one of the brass wind instruments.
Trust
Trust, in law, legal relationship in which property is administered by a trustee, who has some of the powers of an owner, for the benefit of a beneficiary; the trustee is obliged to act only in the beneficiary's best interest and can derive no advantage except an agreed upon fee.
Trust territory
Trust territory, formerly dependent territory administered under United Nations supervision.
Sojourner Truth
Truth, Sojourner (1797?–1883), U.S. abolitionist and feminist.
Truth table
Truth table, systematic tabulation of all the possible input/output combinations produced by a binary circuit.
Trypanosome
Trypanosome, microscopic unicellular parasite that infests the blood plasma of animals and humans, producing disease; it is transmitted by insects.
Tsar
Tsar, or czar, English spellings of the Russian word for “emperor.” The term is used for the rulers of Russia from 1547 to 1917.
Peter Ilich Tschaikowsky
Tschaikowsky, Peter Ilich See: Tchaikovsky, Peter Ilich.
Tsetse fly
Tsetse fly, name for 20 species of muscoid flies (genus Glossina).
Moise Kapenda Tshombe
Tshombe, Moise Kapenda (1919–69), president (1960–63) of the Congolese breakaway state of Katanga.
Tsimshian
Tsimshian, Native American tribe, residing in British Columbia along the Nass and Skeena rivers.
Tuamotu Islands
Tuamotu Islands, group of 75–80 small islands and atolls spanning nearly 1,000 mi (1,609 km) in the South Pacific Ocean.
Tuareg
Tuareg, Berber tribe in the Sahara.
Tuatara
Tuatara (Sphenodon punctatus), reptile resembling the lizard.
Tuba
Tuba, low-pitched brass musical wind instrument with three to five valves.
Tuber
Tuber, swollen, underground stem or root that contains stored food material; they are prennial.
Tuberculosis
Tuberculosis (TB), group of infectious diseases caused by the bacillus Mycobacterium tuberculosis, which kills some 3 million people every year throughout the world. TB may invade any organ but most commonly affects the respiratory system, where it has been called consumption or phthisis. In 1906 it killed 1 in every 500 persons in the United States, but today it leads to only 1 in 30,000 deaths b…
Tuberose
Tuberose (Polianthes tuberosa), tropical plant of the agave family, native to Asia and America but cultivated elsewhere for its use in perfumes and other products.
Harriet Tubman
Tubman, Harriet (c.1820–1913), U.S. abolitionist.
William Vacanarat Shadrach Tubman
Tubman, William Vacanarat Shadrach (1895–1971), president of Liberia (1944–71).
Richard Tucker
Tucker, Richard (1914–75), U.S. opera singer.
Tucson
Tucson (pop. 415,100), city in southeast Arizona, inc. 1877.
Antony Tudor
Tudor, Antony (1909–87), English choreographer who introduced dramatic, emotional themes into U.S. ballet.
House of Tudor
Tudor, House of, reigning dynasty of England (1485–1603).
Tuileries
Tuileries, former royal palace in Paris.
Tularemia
Tularemia, or rabbit fever, infectious disease due to bacteria (Pasteurella tularensis), causing fever, ulceration, lymph node enlargement, and sometimes pneumonia.
Tulip
Tulip, name for plant (genus Tulipa) native to Europe and Asia, grown from bulbs.
Tuliptree
Tuliptree See: Yellow poplar.
Tulsa
Tulsa (pop. 375,300), city in northeast Oklahoma, on the Arkansas River.
Tumbleweed
Tumbleweed, common name for several plants native to North America that grow in clumps on waste land and dry into loose balls.
Tumboa
Tumboa See: Welwitschia.
Tumor
Tumor, or neoplasm, abnormal overgrowth of tissue.
Tuna
Tuna, high-speed fish with rows of finlets on the tail.
Tundra
Tundra, plains of the Arctic Circle.
Tungsten
Tungsten, or wolfram, chemical element, symbol W; for physical constants see Periodic Table.
Tunis
Tunis (pop. 596,700), capital city of Tunisia, on the Lake of Tunis, in northeastern Tunisia.
Tunisia
Tunisia, republic in North Africa. With an area of some 63,362 sq mi (164,150 sq km), Tunisia is bounded on the south by Libya, on the west by Algeria, and on the north and east by the Mediterranean Sea. The Cape Bon peninsula, in the extreme northeast, is only 96 mi (153 km) from Sicily. Tunis is the capital and chief port. Tunisia's irregular coastline has several good harbors, among them…
Tunnel
Tunnel, underground passageway usually designed to carry a highway or railroad, to serve as a conduit for water or sewage, or to provide access to an underground working face. Although tunnels have been built since prehistoric times, tunneling methods remained primitive and hazardous until the 19th century. Modern softground tunneling was pioneered by Marc Brunel, who invented the “tunnelin…
Gene Tunney
Tunney, Gene (James Joseph Tunney; 1898–1978), U.S. world heavyweight boxing champion (1926–28).
Tunny
Tunny See: Tuna.
Tupí-Guaraní
Tupí-Guaraní, group of Native American tribes from central and eastern South America.
Tupelo
Tupelo, name of several trees belonging to the Nyssaceae family, found in Southeast Asia and in North America.
Sir Charles Tupper
Tupper, Sir Charles (1821–1915), Canadian politican and one of the founders of the Dominion of Canada.
Turbine
Turbine, machine for directly converting the kinetic and/or thermal energy of a flowing fluid (air, hot gas, steam, or water) into useful rotational energy. The working fluid either pushes against a set of blades mounted on the drive shaft (impulse turbines) or turns the shaft by reaction when the fluid is expelled from nozzles (or nozzle-shaped vanes) around its circumference (reaction turbines).…
Turbojet
Turbojet See: Jet propulsion.
Turbot
Turbot (Psetta maxima), large flatfish found in the North Sea and Icelandic waters.
Ivan Turgenev
Turgenev, Ivan (1818–83), Russian writer whose realistic portrayals of the peasants and nobility of his country helped bring about social reforms and influenced later Russian writers.
Turin
Turin (pop. 952,700), city in northwestern Italy.
or Turkistan Turkestan
Turkestan, or Turkistan, large region in Asia covering parts of China, the former USSR, and Afghanistan.
Turkey
Turkey, republic occupying Asia Minor and a small part of southeastern Europe. Lying between the Black and the Mediterranean seas, the Asian and European parts of Turkey are separated by the Straits, a waterway consisting of the Bosporus, the Sea of Marmara, and the Dardanelles. The Straits strategically link the Black Sea with the Mediterranean Sea. Covering 301,382 sq mi (780,574 sq km), Turkey …
Turkey
Turkey, name of two species of large New World game birds, family Meleagrididae.
Turkish
Turkish, Turkic language, official language of Turkey, also spoken by minorities in eastern Europe and southwestern Asia.
Turkmenistan
Turkmenistan (Republic of), independent country in central Asia, bordering Kazakhstan and Uzbekistan in the north, Afghanistan in the southeast, Iran in the south, and the Caspian Sea in the west. The Kara Kum desert covers about 90% of the landmass in this region. The country has a desert climate with hot summers and cold winters. Most of the population are Muslims, who speak a Turkic lang…
Turks
Turks, family to Turkic-speaking, chiefly Muslim people extending from Sinkiang (west China) and Siberia to Turkey, Iran, and former East European USSR.
Turks and Caicos Islands
Turks and Caicos Islands, two British colonial island groups in the West Indies.
Frederick Jackson Turner
Turner, Frederick Jackson (1861–1932), U.S. historian.
J(oseph) M(allard) W(illiam) Turner
Turner, J(oseph) M(allard) W(illiam) (1775–1851), English Romantic landscape painter.
John Napier Turner
Turner, John Napier (1929– ), prime minister of Canada following the resignation of Prime Minister Pierre Trudeau.
Nat Turner
Turner, Nat (1800–31), U.S. slave and revolutionary.
Turnip
Turnip, plant (genus Brassica) native to Europe and Asia.
Turnstone
Turnstone, one of two types of shore birds belonging to the sandpiper family.
Turquoise
Turquoise, AL2(OH)3PO4H2O+Cu, igneous (volcanic) mineral containing aluminum, copper, and phosphorus, found in arid regions of the earth, especially Iran, the Sinai Peninsula, and the North American Southwest.
Turtle
Turtle, reptile (order Chelonia) with a shell that almost encloses the body. A land turtle is sometimes called a tortoise, and some freshwater turtles are given the name terrapin. The turtle has existed for more than 175 million years, and there are now about 230 species spread over the warmer parts of the world, 44 of them in the United States. Some species are becoming rare because they are hunt…
Turtledove
Turtledove, woodland bird belonging to the pigeon and dove family.
Tuscany
Tuscany, region in west-central Italy, extending from the Apennine Mountains to the west coast.
Tuscarora
Tuscarora, North American Native American tribe.
Tussock moth
Tussock moth, type of moth belonging to the Lymantriidae family.
Tutankhamen
Tutankhamen (fl.c. 1350 B.C.), Egyptian pharaoh.
Desmond Tutu
Tutu, Desmond (1931– ), South African black minister, recipient of the 1984 Nobel Peace Prize.
Tutuila
Tutuila See: American Samoa.
Tuva
Tuva, republic of the Russian Federation between Siberia and Mongolia.
Tuvalu
Tuvalu (formerly Ellice Islands), independent Commonwealth nation composed of nine small atolls spread over more than 500,000 sq mi (1,295,000 sq km) in the West Pacific. The capital is Fongafale on Funafuti. The largest island, Vaitupu, covers only 2 sq mi (5.2 sq km). No spot on these coral atolls rises more than 16 ft (4.9 m) above sea level. The soil is poor and there are no rivers and little …
TV
TV See: Television.
TVA
TVA See: Tennessee Valley Authority.
Mark Twain
Twain, Mark (Samuel Langhorne Clemens; 1835–1910), U.S. author and popular humorist and lecturer.
Tweed River
Tweed River, waterway forming part of the Scotland-England border.
William Marcy ‘Boss’ Tweed
Tweed, William Marcy ‘Boss’ (1823–78), U.S. politician.
Laws of the Twelve Tables
Twelve Tables, Laws of the, earliest Roman code of laws.
Twelve-tone music
Twelve-tone music, or serial music, type of music developed in the 1920s that rejects tonality as the basis for composition.
Twelve Tribes
Twelve Tribes, twelve family groups into which the ancient Hebrews were divided.
John Tyler
Tyler, John (1790–1862), 10th president of the United States. Tyler, the first United States vice president to step into the presidency on a president's death in office, entered politics as a Democrat but was elected as a Whig. As president, however, he so opposed the Whigs' program that he was expelled from the party, burned in effigy, and threatened with impeachment. Most of…
Moses Coit Tyler
Tyler, Moses Coit (1835–1900), critic and historian of early U.S. literature.
Wat Tyler
Tyler, Wat (d. 1381), leader of the English Peasant's Revolt (1381), England's first popular rebellion.
Sir Edward Burnett Tylor
Tylor, Sir Edward Burnett (1832–1917), British anthropologist.
William Tyndale
Tyndale, William (c. 1494–1536), English biblical translator.
Type
Type, characters, including letters, numbers, and punctuation marks, assembled to form words and sentences in the printing of books, magazines, and newspapers.
Typewriter
Typewriter, writing machine activated manually or electrically by means of a keyboard.
Typhoid fever
Typhoid fever, infectious disease due to Salmonella typhosa, causing fever, a characteristic rash, lymph node and spleen enlargement, gastrointestinal tract disturbance with bleeding and ulceration, and usually marked malaise or prostration.
Typhus
Typhus, infectious disease caused by rickettsia and carried by lice, leading to a feverish illness with a rash.
Tyrannosaurus
Tyrannosaurus See: Dinosaur; Prehistoric animal.
Tyre
Tyre, or Sur (pop. 23,000), town in southwest Lebanon, situated on the eastern end of the Mediterranean Sea.
Tyrol
Tyrol, or Tirol, state in western Austria.
William Tyron
Tyron, William (1729–88), English governor of North Carolina (1765–71).
Tyrrhenian Sea
Tyrrhenian Sea, part of the Mediterranean Sea bounded by the west coast of Italy and by the islands of Corsica, Sardinia, and Sicily.
Mike Tyson
Tyson, Mike (1966– ), U.S. boxer.
Mike Tyson
Tyson, Mike (1966– ), U.S. boxer.
U
U, 21st letter of the English alphabet, corresponding to the Semitic letter waw, meaning “hook,” represented by a tenthook symbol and probably derived from an ancient Egyptian symbol for a pole support.
U-2
U-2, U.S. spy plane used during the 1950s and 1960s.
U- (235)
U-235, any of the different forms of an isotope of the element uranium with a mass number of 235 (the number of protons and neutrons in the atom's nucleus).
U- (238)
U-238 See: Uranium.
U-boat
U-boat See: Submarine.
U.A.R.
U.A.R.
Ubangi River
Ubangi River, chief northern tributary of the Zaire (Congo) River, in central Africa.
Ucayali River
Ucayali River, chief headstream of the Amazon, in northern Peru.
Paolo Uccello
Uccello, Paolo (c. 1397–1475), Florentine early Renaissance painter, noted for his use of perspective.
Nicolas Udall
Udall, Nicolas (1505–56), English schoolmaster, scholar, and playwright.
Uffizi Palace
Uffizi Palace, 16th-century palace in Florence, Italy, built by Giorgio Vassari for Cosimo I de' Medici as a public office building.
UFO
UFO See: Unidentified flying object.
Uganda
Uganda, landlocked republic in east-central Africa. Covering 93,070 sq mi (241,040 sq km), Uganda is bordered by Tanzania and Rwanda in the south, Sudan in the north, Zaire in the west, and Kenya in the east. The capital is Kampala. More than 80% of the land area of Uganda consists of a fertile plateau some 3,000 to 5,000 ft (914–1,524 m) above sea level, with highlands to the east a…
Ugarit
Ugarit, ancient capital city of the Ugarit Kingdom of northwestern Syria, discovered in 1929 by French archeologists.
UHF waves
UHF waves See: Ultrahigh frequency waves.
Ukraine
Ukraine (Republic of), independent country in Eastern Europe, bordered by Poland to the northwest; by Slovakia, Hungary, Romania, and Moldavia to the southwest; by the Black Sea and the Sea of Azov to the south; by Russia to the northeast and east; and by Byelorussia to the north. The capital is Kiev. Ukraine consists for a large part of lowlands, with mountains on the Crimean and in the west: the…
Ukranian
Ukranian, East Slavic language of the Slavonic group, closely related to Russian, from which it diverged c.1200.
Ukulele
Ukulele, small guitarlike instrument.
Ulan Bator
Ulan Bator (pop. 619,000), capital and largest city of Mongolia.
Galina Ulanova
Ulanova, Galina (1910–98), Russian prima ballerina of the Bolshoi Theater, Moscow (1944–62).
Walter Ulbricht
Ulbricht, Walter (1893–1973), leader of post-World War II East Germany.
Ulcer
Ulcer, pathological defect in skin or mucous membrane caused by inflammation due to infection, loss of blood supply, failure of venous circulation, or cancer.
Ultima Thule
Ultima Thule, ancient Greek and Roman name for lands of the far north.
Ultrahigh frequency waves
Ultrahigh frequency waves (UHF), radio waves with frequencies from 300 to 3,000 megahertz (1 megahertz equals 1 million cycles per second) and with short ranges, usually less than 50 mi (80 km).
Ultramicroscope
Ultramicroscope, special microscope used for studying colloidal particles (particles in solution or suspension) too small to be seen with a regular-light microscope.
Ultrasonics
Ultrasonics, science of sound waves with frequencies above those that humans can hear (above 20,000 cycles per second).
Ultraviolet rays
Ultraviolet rays, invisible light lying beyond the violet end of the spectrum.
Ulysses
Ulysses, or Odysseus, legendary hero of ancient Greece, son and successor of King Laertes of Ithaca, and husband of Penelope.
Umbilical cord
Umbilical cord, in mammals, tubelike structure linking the developing embryo, or fetus, to the placenta through most of pregnancy.
Umbrellabird
Umbrellabird, any of several crowlike birds (genus Cephalopterus) of tropical American forests, especially C. ornatus, whose crest can be expanded into an “umbrella.” It also has a lappet of feathers hanging from the throat.
UN
UN See: United Nations.
Un-American Activities Committee
Un-American Activities Committee (HUAC), committee of the U.S.
Miguel de Unamuno
Unamuno, Miguel de (1864–1936), Spanish philosopher and writer, rector of Salamanca University from 1900 to his death.
Uncas
Uncas (1588?–1683), chief of the Mohegans of Connecticut, celebrated in James Fenimore Cooper's The Last of the Mohicans (1826).
Uncle Sam
Uncle Sam, popular figure developed by 19th-century cartoonists and officially adopted as a U.S. national symbol in 1961.
Unconscious
Unconscious, in psychology, that part of the mind the individual is unable to recall at will.
Underground
Underground, term generally used for any secret political movement that seeks to overthrow a country's existing government or military authority.
Underground Railroad
Underground Railroad, secret network that helped U.S. slaves to escape from the South to the northern states and to Canada before the Civil War.
Sigrid Undset
Undset, Sigrid (1882–1949), Norwegian novelist.
Undulant fever
Undulant fever See: Brucellosis.
Unemployment
Unemployment, situation in which people who are normally part of the labor force are unable to find jobs.
Unemployment insurance
Unemployment insurance, type of Social Security providing income to people involuntarily unemployed.
UNESCO
UNESCO See: United Nations Educational, Scientific, and Cultural Organization.
Ungulate
Ungulate, term for any mammal with hoofs.
UNICEF
UNICEF See: United Nations Children's Fund.
Unicorn
Unicorn, mythical creature with the body of a horse and one horn on its forehead.
Unicycle
Unicycle, single-wheeled vehicle with pedals, a seat mounted above the wheel, and no handlebars.
Unidentified flying object
Unidentified flying object (UFO), object or light reprotedly seen in the air during day or night that cannot always be explained by conventional phenomena.
Unification Church
Unification Church, religious organization of Korean origin that became highly visible in the United States in the late 1960s.
Uniform Code of Military Justice
Uniform Code of Military Justice, body of law governing all members of the U.S. armed forces.
Uniformitarianism
Uniformitarianism, doctrine in geology originally opposed to Catastrophism.
Act of Union
Union, Act of, British Parliamentary act of 1840 that officially united Upper Canada and Lower Canada.
Union of South Africa
Union of South Africa See: South Africa.
Union of Soviet Socialist Republics
Union of Soviet Socialist Republics (USSR) also known as the Soviet Union. Name of a union of 15 Soviet republics that desintegrated in 1991. Now independent countries, the constituent republics were Armenia, Azerbaijan, Estonia, Georgia, Kazachstan, Kirgizstan, Latvia, Lithuania, Moldova, Russian Federation, Turkmenistan, Ukraine and Uzbekistan. The union covered more than half of Europe and two-…
labor Unions
Unions, labor, workers' organizations formed to improve pay, working conditions, and benefits through collective power. Modern labor unions arose out of the concentrations of workers created by the Industrial Revolution. A craft (horizontal) union organizes workers by their particular skill; an industrial (vertical) union includes all workers in an industry. Unions negotiate contracts with …
Unitarianism
Unitarianism, unorthodox Protestant faith that rejects the Trinity and the divine nature of Christ, and asserts the unipersonality of God.
John Unitas
Unitas, John (1933– ), U.S. football player.
United Arab Emirates
United Arab Emirates, federation of emirates in the eastern Arabian Peninsula, bordered in the north by the Persian Gulf, in the east by the Gulf of Oman, in the south by Oman, in the south and west by Saudi Arabia, and in the northwest by Qatar. It comprises Abu Dhabi, Ajman, Dubai, Fujairah, Ras al-Khaimah, Sharjah, and Umm al-Qaiwain. The city of Abu Dhabi is the capital. The indigenous populat…
United Arab Republic
United Arab Republic (UAR), union of Egypt and Syria proclaimed in 1958 as a step toward Arab unity.
United Automobile Workers
United Automobile Workers (United Automobile, Aerospace and Agricultural Implement Workers of America), second-largest U.S. industrial labor union, with local affiliates in Canada.
United Church of Canada
United Church of Canada, Protestant church formed in 1925 by the union of Methodist and most Presbyterian and Congregationalist churches.
United Church of Christ
United Church of Christ, U.S.