Ångström (Å)
Ångström (Å), unit used to measure the length of light waves and other extremely small dimensions, named for Swedish physicist Anders Jonas Ångström.
21st Century Webster's Family Encyclopedia - Anderson, Elizabeth Garrett to Arctic tern
Anders Jonas Ångström
Ångström, Anders Jonas (1814–74), Swedish physicist, one of the founders of spectroscopy (spectrum analysis) and the first to identify hydrogen in the solar spectrum (1862).
Elizabeth Garrett Anderson
Anderson, Elizabeth Garrett (1836–1917), one of the first English women to become a doctor (1865).
John Bayard Anderson
Anderson, John Bayard (1922–), U.S. politician.
Marian Anderson
Anderson, Marian (1902–93), U.S. contralto.
Maxwell Anderson
Anderson, Maxwell (1888–1959), U.S. playwright.
Sherwood Anderson
Anderson, Sherwood (1876–1941), U.S. writer whose novels and short stories deal largely with the rebellion of individuals against contemporary industrial society.
Andes
Andes, South America's largest mountain system, 4,500 mi (7,200 km) long and averaging 200–250 mi (320–400 km) wide, near the west coast and running almost the entire length of the continent.
Andorra
Andorra (pop. 61,000), tiny European principality (180 sq mi/465 sq km) in the eastern Pyrenees along the border between France and Spain. The Andorrans speak Catalan, French, and Spanish. Andorra uses both the French franc and the Spanish peseta as currency. The country attained autonomous status under Charlemagne, and since 1278 has been a co-principality, under the joint sovereignty of the Bish…
John André
André, John (1750–80), English army officer, hanged as a spy by the Americans during the Revolutionary War.
José Bonifácio de Andrada é Silva
Andrada é Silva, José Bonifácio de (1763–1838), Brazilian geologist and statesman, known as the father of Brazilian independence.
Andrea del Sarto
Andrea del Sarto (1486–1531), leading 16th-century Florentine painter, influenced by Michelangelo and Albrecht Dürer and renowned for delicately colored church frescoes.
Andrea Doria
Andrea Doria, Italian luxury liner that sank on July 26, 1956, following an inexplicable collision with the Stockholm, a Swedish liner, about 45 mi (72 km) south of Nantucket Island; 51 people died.
Mario Andretti
Andretti, Mario (1940–), Italian-born U.S. race car driver.
John Albion Andrew
Andrew, John Albion (1818–67), U.S. statesman and antislavery proponent.
Saint Andrew
Andrew, Saint (1st century A.D.), one of Jesus's 12 Apostles, formerly a fisherman and disciple of John the Baptist.
Andrews Air Force Base
Andrews Air Force Base, headquarters for Air Force Systems Command.
Charles McLean Andrews
Andrews, Charles McLean (1863–1943), U.S. historian.
Roy Chapman Andrews
Andrews, Roy Chapman (1884–1960), U.S. naturalist, explorer, and author.
Leonid Nikolayevich Andreyev
Andreyev, Leonid Nikolayevich (1871–1919), Russian novelist, short-story writer, and playwright.
Ivo Andric
Andric, Ivo (1892–1975), Yugoslav novelist who won the Nobel Prize for literature in 1961, largely for the epic quality of The Bridge on the Drina.
Androcles
Androcles, in Roman legend, slave who was thrown to the wild animals in the Roman arena but was spared by a lion from whose paw he had once extracted a thorn.
Androgen
Androgen See: Hormone.
Andromache
Andromache, in Greek mythology, wife of Hector, prince and hero of Troy.
Andromeda
Andromeda, spiral galaxy visible in the Andromeda constellation.
Andromeda
Andromeda, in Greek mythology, daughter of Cassiopeia and Cepheus, king of Ethiopia.
Yuri Vladimirovich Andropov
Andropov, Yuri Vladimirovich (1914–84), Soviet political leader, who became general secretary of the Communist party in 1982 after the death of Leonid Brezhnev and also, in 1983, chief of state.
Sir Edmund Andros
Andros, Sir Edmund (1637–1714), British governor of New York (1674–81) and the Dominion of New England (1686–89).
Anemia
Anemia, deficiency in the number of red blood cells or their hemoglobin content (the red substance that binds with oxygen), or both.
Anemometer
Anemometer, instrument for measuring wind speed.
Anemone
Anemone, genus of wild or cultivated perennial herbs of the buttercup family (Ranunculaceae).
Anesthesia
Anesthesia, loss of sensation, especially the sensation of pain.
Anesthesiology
Anesthesiology, branch of medicine that deals with the administration before and during childbirth or surgery of anesthetics, drugs that dull or block sensation or anxiety.
Aneurysm
Aneurysm, localized dilation of a blood vessel, usually an artery, due to local fault in the wall through defect, disease, or injury, producing a pulsating swelling over which a murmur may be heard.
Angel
Angel, supernatural messenger and servant of the deity.
Angel Falls
Angel Falls, world's highest known waterfall (3,212ft/979 m), on the Churin River in southeastern Venezuela, discovered by U.S. aviator Jimmy Angel in 1935.
Angelfish
Angelfish, any of a group of freshwater tropical fish, and of several fish found in warm seas (family Chaetodontidae).
Sir Norman Angell
Angell, Sir Norman (1874–1967), English economist and internationalist, awarded the Nobel Peace Prize in 1933.
Maya Angelou
Angelou, Maya (1928–), U.S. author best known for her autobiographical books I Know Why the Caged Bird Sings (1970) and Gather Together in My Name (1974), which recount her struggles for identity as an African American in a hostile world.
Angevin
Angevin, name of 2 medieval royal dynasties originating in the Anjou region of western France.
Angina pectoris
Angina pectoris, severe but temporary attack of heart pain that occurs when the demand for oxygen by the heart muscle exceeds the ability of the coronary vessels to supply oxygen, due to narrowing or blockage of the vessels.
Angiography
Angiography, technique allowing visualization of blood vessels on X rays after injection of a radiopaque substance (one that shows up on X ray).
Angioplasty
Angioplasty, set of techniques used in reconstructing damaged blood vessels, which may involve surgery, lasers, or tiny inflatable balloons.
Angiosperm
Angiosperm, member of a large class of seed-bearing plants (the flowering plants), its seeds developing completely enclosed in the tissue of the parent plant (rather than unprotected, as in the only other seed-bearing group, the gymnosperms).
Angkor
Angkor, extensive ruins from the ancient Khmer Empire in northwestern Cambodia, covering 40 sq mi (100 sq km).
Angle
Angle, in plane geometry, the figure formed by the intersection of two straight lines. The point of intersection is known as the vertex. If the two lines are viewed as radii of a circle of unit radius, the magnitude of an angle can be defined in terms of the proportion of the circle's circumference cut off by the two lines. Angles are measured in radians or degrees. One radian is the magnit…
Angles
Angles, Germanic tribe from which England derives its name.
Anglicans
Anglicans, community of churches developed from the Church of England.
Anglo-Saxons
Anglo-Saxons, collective name for the Germanic peoples who dominated England from the 5th to the 11th centuries.
Angola
Angola (Republic of), independent state in southwest Africa; bordered by the Atlantic Ocean in the west, Zaire in the north, Zambia in the east, and Namibia in the south. Angola is dominated by the Bié Plateau, some 4,000 ft (1,219 m) above sea level, which occasionally rises to altitudes of 8,000 ft (2,438 m) or more. To the north are tropical rain forests; to the south, semiarid or desert…
Angora
Angora See: Ankara.
Angora
Angora, term used for the long-haired varieties of goats, cats, and rabbits.
Anguilla
Anguilla (pop. 9,000), island in the West Indies, 35 sq mi (90 sq km), lying 150 mi (240 km) east of Puerto Rico.
Anhinga
Anhinga, also called darter, snakebird, or water turkey, large bird of the anhinga family that feeds in waters from southeast and southcentral United States to Argentina.
Anhydride
Anhydride, oxide that forms an acid or base when it reacts with water.
Anhydrous ammonia
Anhydrous ammonia, dry or liquid form of ammonia, made by compressing pure ammonia gas (NH3) and used as nitrogen fertilizer and as a refrigerant.
Ani
Ani, or tickbird, any of a genus (Crotophaga) of long-tailed black cuckoos native to the warm regions of the Americas.
Aniakchack
Aniakchack, volcano on the Alaska Peninsula, in the Aleutian mountain range.
Aniline
Aniline, chemical compound (C6H5NH2) obtained from indigo or other organic substances, or from benzol, and used in the production of dyes.
Animal
Animal, living organism distinguished from plants by locomotion, environmental reactivity, nutrient absorption, and cell structure. Animals move freely using a wide variety of mechanisms to do so, whereas plants are rooted to one place. Animals sense their environments and react to them. In the case of multicellular animals, they react by means of the nervous system; in more highly developed anima…
Animation
Animation, cinematographic technique creating the illusion of movement by projection of a series of drawings or photographs showing successive views of an action.
Animism
Animism, term first used by anthropologist E.B.
Anise
Anise, herb of the carrot family that yields seeds with a spicy, licorice flavor.
Ankara
Ankara (pop. 2,559,500), capital of Turkey and of Ankara province in Asia Minor.
Ankle
Ankle, joint connecting the foot and the leg.
Ann Arbor
Ann Arbor (pop. 282,937), city in southeastern Michigan, seat of Washtenaw County, and home of the University of Michigan since 1841.
Anna
Anna, in the New Testament (Luke 2), Jewish prophetess, daughter of Phanuel of the tribe of Asher.
Anna Ivanovna
Anna Ivanovna (1693–1740), empress of Russia from 1730.
Annapolis
Annapolis (pop. 31,700), capital of Maryland, seat of Anne Arundel County on the Severn River near Chesapeake Bay.
Annapolis
See also: United States Naval Academy.
Annapolis Convention
Annapolis Convention (1786), meeting in Annapolis, Md., to discuss interstate commerce.
Annapolis Royal
Annapolis Royal (pop. 630), town on the Annapolis River, west coast of Nova Scotia, near the site of the earliest permanent French settlement in Canada.
Annapurna
Annapurna, Himalayan mountain in Nepal with the world's 11th-highest peak (26,391 ft/8,044 m).
Anne
Anne (1665–1714), queen of Great Britain and Ireland (1702–14), last of the Stuart monarchs.
Anne of Austria
Anne of Austria (1601–66), queen consort and regent of France.
Anne of Brittany
Anne of Brittany (1477–1514), duchess of Brittany and queen of France.
Anne of Cleves
Anne of Cleves (1515–57), queen consort and fourth wife of England's Henry VIII.
Saint Anne
Anne, Saint, mother of the Virgin Mary and wife of St.
Walter Annenberg
Annenberg, Walter (1908–), U.S. publisher.
Annexation
Annexation, acquisition by a country of a territory previously outside its jurisdiction.
Anno Domini
Anno Domini See: A.D.
Annual
Annual, plant that completes its life cycle in one growing season, as contrasted with biennials (two seasons) and perennials (more than two).
Annual rings
Annual rings, rings of dark and light wood seen across the trunk of a tree that has been cut down.
Annuity
Annuity, yearly payment a person receives for life or for a term of years, the person usually being entitled to such payment in consideration of money advanced to those who pay.
Annulment
Annulment, decree to the effect that a marriage was invalid when contracted.
Annunciation
Annunciation, in Christian belief, the archangel Gabriel's announcement to the Virgin Mary that she would give birth to the Messiah.
Gabriele d' Annunzio
Annunzio, Gabriele d' See: D'Annunzio, Gabriele.
Anodizing
Anodizing, electrolytic method of producing a corrosion-resistant or decorative layer of oxide on a metal, usually aluminum.
Anorexia nervosa
Anorexia nervosa, psychological disorder characterized by a disturbed sense of body image and exaggerated anxiety about weight gain, manifested by abnormal refusal to eat, leading to severe weight loss, and, in women, amenorrhea (loss of period).
Jean Anouilh
Anouilh, Jean (1910–87), French playwright, whose highly theatrical dramas emphasize the dilemma of modern times, in which individuals are forced to compromise their dreams.
Anoxia
Anoxia, severe hypoxia (lowered oxygen levels in body tissues), whether due to lack of oxygen in air inhaled or lack of oxygen available in the blood or tissues.
Saint Anselm
Anselm, Saint (1033?–1109), archbishop of Canterbury (from 1093), a founder of Scholasticism.
Ernest Ansermet
Ansermet, Ernest (1883–1969), Swiss orchestral conductor who directed many premieres of Stravinsky ballets.
Shloime Ansky
Ansky, Shloime (Solomon Samuel Rapoport; 1863–1920), Russian Yiddish author and playwright, best known for The Dybbuk (1916), a tragedy of demonic possession.
Ant
Ant, insect of order Hymenoptera (which also includes bees and wasps), family Formicidae, living in communities consisting of males, females, and infertile worker females. An ant colony may contain thousands and even millions of ants organized into a highly socialized community. The queen ant's function is to produce eggs. The female worker ant (there are no male worker ants) is responsible…
Ant lion
Ant lion, or doodlebug, larval form of any of several insects of the Myrme-leontidae family that traps ants and other prey in pits dug in sandy soil.
Antananarivo
Antananarivo, or Tananarive (pop. 803,400), capital and largest city of Madagascar.
Antarctic
Antarctic See: Antarctica.
Antarctic Circle
Antarctic Circle, imaginary boundary, 66°30' S lat., marking the northernmost latitude of the Antarctic region at which the sun remains above the horizon at least one day a year, the December solstice, and the southernmost latitude at which the sun is visible at the June solstice.
Antarctic Ocean
Antarctic Ocean, ocean surrounding the Antarctic continent, also called the Southern Ocean; sometimes not considered to be a separate ocean but rather a part of the Atlantic, Indian, and Pacific oceans.
Antarctica
Antarctica, fifth largest continent, almost 6,000,000 sq mi (17,400,000 sq km). Antarctica is almost entirely covered by an ice cap up to 14,000 ft (4,267 m) thick except where the ice is pierced by mountain peaks. The Vinson Massif is Antarctica's highest mountain (16,900 ft /5,150 m). The continent is circular, indented by the arc-shaped Weddell Sea (south of the Atlantic Ocean) and the r…
Antares
Antares, one of the brightest stars in the southern sky, in the constellation Scorpio.
Anteater
Anteater, any of 3 genera of Central and South American mammals, family Myrmecophagidae, order Edentata, including the giant anteater and the tamandua.
Antelope
Antelope, swift-moving hollow-horned ruminant of the family Bovidae, order Artiodactyla.
Antenna
Antenna, or aerial, component in an electrical circuit that radiates or receives radio waves.
Antennae
Antennae, paired sensory appendage on the head of most insects, crustaceans, and other arthropods.
George Antheil
Antheil, George (1900–59), U.S. composer.
Anthemius of Tralles
Anthemius of Tralles (d. c.534), Byzantine architect, mathematician, and physicist.
Saint Anthony of Padua
Anthony of Padua, Saint (1195–1231), Franciscan friar, theologian, and preacher.
Susan Brownell Anthony
Anthony, Susan Brownell (1820–1906), major U.S. leader and organizer of the fight for women's rights.
Saint Anthony of Thebes
Anthony of Thebes, Saint (c.250–350), Egyptian hermit, considered the founder of Christian monasticism.
Anthrax
Anthrax, infectious disease affecting livestock and, more rarely, humans, causing skin pustules and lung damage.
Anthropoid
Anthropoid See: Primate.
Anthropology
Anthropology, study of the origins, evolution, and development of human beings and their various cultures and societies. Physical anthropology is concerned with human beings as physical organisms, the place of Homo sapiens in the framework of evolution, and the classification of early humans based upon the study of fossil remains. Cultural anthropology examines the specific knowledge, values, and …
Anti-Defamation League
Anti-Defamation League See: B'nai B'rith.
Anti-Federalists
Anti-Federalists, opponents of the ratification of the Federal Constitution of 1787.
Anti-Masonic Party
Anti-Masonic Party, U.S. political party (1827–36), formed to oppose Freemasons in politics.
Anti-Monopoly Party
Anti-Monopoly Party, U.S. political party opposing monopolies in business in 1884.
Anti-Semitism
Anti-Semitism, systematic hostility to Jews.
Anti-war movement
Anti-war movement, opposition to U.S. involvement in the Vietnam war.
Antiaircraft defense
Antiaircraft defense, method of protection from attack by enemy aircraft or missiles, involving early detection and interference and destruction.
Antibiotic
Antibiotic, any of the substances, usually produced by microorganisms, that kill or prevent the growth of other microorganisms, especially bacteria and fungi.
Antibody
Antibody See: Immunity.
Antichrist
Antichrist, in Christian belief, the human antagonist of Christ.
Anticoagulant
Anticoagulant, substance that interferes with blood clotting, used to treat or prevent strokes and embolism.
Antidote
Antidote, remedy that neutralizes a poison or counteracts its effects.
Battle of Antietam
Antietam, Battle of See: Civil War, U.S.
Antifreeze
Antifreeze, substance added to a solvent to prevent it from freezing in cold weather.
Antigen
Antigen, foreign substance introduced into an organism, stimulating the production of antibodies that combat the intruder.
Antigone
Antigone, in Greek mythology, daughter of Oedipus and Jocasta.
Antigonid dynasty
Antigonid dynasty, line of kings that ruled Macedonia (northern Greece) 294 B.C.–168 B.C.
Antigravity
Antigravity, hypothetical force of repulsion described in science fiction but never scientifically observed.
Antigua
Antigua, also called Antigua Guatemala (pop. 15,800), city in south central Guatemala, once the capital.
Antigua and Barbuda
Antigua and Barbuda, island nation in the West Indies, largest and most developed of the Leeward Islands. The islands of Antigua, Barbuda, and Redonda (uninhabited), are of volcanic origin. White sandy beaches fringe the coasts; few places rise to more than 1,000 ft (2,048 m) above sea level. The climate is tropical with a dry season July-Dec. The population is predominantly of African and British…
Antihistamine
Antihistamine, drug used to neutralize the effects of histamine (an organic compound released by certain cells that causes tissue swelling, hives, and severe itching).
The Antilles
Antilles, The, islands of the West Indies, with the exception of the Bahamas.
Antimatter
Antimatter, material composed of antiparticles, which are identical in mass and behavior to electrons, protons, and neutrons but have opposite electrical charges.
Antimony
Antimony, chemical element, symbol Sb; for physical constants see Periodic Table.
Antioch
Antioch (pop. 94,900), ancient city in Asia Minor, now known as Antakya, in southern Turkey on the Orontes River.
Antipodes
Antipodes (Greek, “foot-to-foot”), 2 places exactly opposite each other on the globe, so that a straight line connecting them would pass through the center of the earth.
Antique
Antique, object that has acquired value through a combination of age, rarity, craft, and historic interest.
Antirenters
Antirenters, group of tenant farmers in New York State who protested against paying rent to landlords (1839–1847).
Antiseptic
Antiseptic, substance that kills or prevents the growth of microorganisms (particularly bacteria and fungi), especially used to avoid sepsis (infection) from contamination of body surfaces and surgical instruments.
Antitoxin
Antitoxin, antibody released into the bloodstream to counteract the poisonous products (toxins) of invading bacteria.
Antitrust laws
Antitrust laws, legislation designed to protect competition among businesses.
Antofagasta
Antofagasta (pop. 228,000), major Pacific seaport in northern Chile, capital of Antofagasta province.
Marie Antoinette
Antoinette, Marie See: Marie Antoinette.
Michelangelo Antonioni
Antonioni, Michelangelo (1912–), Italian film director.
Antonius Pius
Antonius Pius (A.D. 86–161), Roman emperor (138–161), tolerant of Christians, the last to achieve relative stability in the empire.
Marc Antony
Antony, Marc (Marcus Antonius; 82–30 B.C.), Roman politician and general.
Antwerp
Antwerp (pop. 462,900), city and leading port, on the Scheldt River in northern Belgium.
Anubis
Anubis, ancient Egyptian god of the dead, usually portrayed as having the head of a dog or jackal.
Anxiety
Anxiety, unpleasant and disturbing emotion, ranging from ill-defined discomfort to panic or a profound sense of impending doom. Anxious people may be irritable, restless, and agitated, or have impulses for physical activity that may be purposeless and aimless. Physical symptoms may include an increase in heart rate and blood pressure, generalized or localized muscle tension, rapid and shallow brea…
Anzio
Anzio (pop. 27,100), Italian fishing port and seaside resort about 30 mi (48 km) south of Rome.
Anzus Pact
Anzus Pact, treaty signed Sept. 1, 1951, by Australia, New Zealand, and the United States for mutual defense in the Pacific.
Aorta
Aorta, the body's main artery, carrying blood from the left ventricle of the heart to the branch arteries that spread throughout the body.
Apache
Apache, Native American tribe of North America's Southwest (since c. 1100), from Athabascan linguistic family.
Apartheid
Apartheid (Afrikaans, “apartness”), policy of racial segregation as employed by the Republic of South Africa, enforced by the dominant white minority. The system separates whites from nonwhites (i.e., Coloreds, or mulattoes; Asiatics; and Africans, or Bantu), nonwhites from each other, and each individual Bantu group. The policy also involves the “separate development” …
Apatosaurus
Apatosaurus, see: Brontosaurus.
Ape
Ape, primate, family Pongidae, closely related to human beings.
Apennine Tunnel
Apennine Tunnel, 11.5-mi (18.5-km) train tunnel in Italy on the Florence-Bologna line; one of the longest train tunnels in the world, built from 1920–34.
Apennines
Apennines, mountain chain forming the backbone of the Italian peninsula and extending into Sicily, about 800 mi (1,287 km) long and 25–80 mi (40–129 km) wide.
Aphasia
Aphasia, partial or total language impairment, in which the comprehension or expression of words is diminished as a result of injury to the brain.
Aphid
Aphid, destructive sap-feeding insect of the aphid family, also known as greenfly or plant louse.
Aphrodite
Aphrodite, in Greek mythology, goddess of love, fertility, and beauty.
Apia
Apia (pop. 36,000), capital and main port of Western Samoa, on the northern coast of Upolu Island.
Apocalypse
Apocalypse, prophetic revelation, usually about the end of the world and the ensuing establishment of a heavenly kingdom.
Apocrypha
Apocrypha, appendix to the King James Version of the Old Testament.
Guillaume Apollinaire
Apollinaire, Guillaume (Wilhelm Apollinaris de Kostrowitzky; 1880–1918), influential French avant-garde poet and critic.
Apollo
Apollo, in Greek mythology, the son of Zeus and Leto, twin of Artemis, and second only to Zeus in that he had the power of the sun as giver of light and life.
Apollo Project
Apollo Project, U.S. space program initiated by President John F.
Apostles
Apostles, the 12 disciples closest to Jesus, whom he chose to proclaim his teaching: Andrew, John, Bartholomew, Judas, Jude, the two Jameses, Matthew, Peter, Philip, Simon, and Thomas.
Apostles' Creed
Apostles' Creed, statement of belief ascribed to Jesus's apostles and maintained in its present form since the early Middle Ages.
Apothecaries' weight
Apothecaries' weight, system of weights once widely used in Great Britain and the United States by druggists, now replaced by the metric system.
Appalachian Mountains
Appalachian Mountains, mountain system of Northeastern America, about 1,800 mi (2,897 km) long and 120–375 mi (193–603 km) wide, stretching south from Newfoundland to central Alabama.
Appalachian National Scenic Trail
Appalachian National Scenic Trail, longest marked hiking trail in the world, stretching over 2,000 mi (3,219 km) along the crest of the Appalachian Mountains from Mt.
Appeal
Appeal, in law, transfer of a case that has been decided in a lower court to a higher court for review.
Appellate court
Appellate court See: Court; Trial.
Appendicitis
Appendicitis, inflammation of the appendix, often caused by obstruction to its narrow opening, followed by swelling and bacterial infection.
Appendix
Appendix, in biology small, hollow, closed tube located where the small and large intestines meet.
Adolphe Appia
Appia, Adolphe (1862–1928), Swiss stage designer whose ideas revolutionized early 20th-century theater.
Appian Way
Appian Way, oldest Roman road, constructed by the censor Appius Claudius Caecus in 312 B.C.
Apple
Apple, tree (genus Malus) of the rose family, widely cultivated in temperate climates; also, the fruit of the tree.
Apple of Sodom
Apple of Sodom (Solanum sodomeum), spiny plant of the nightshade family, native to Palestine, that bears yellow fruit resembling small apples.
Johnny Appleseed
Appleseed, Johnny (John Chapman; 1774–1845), U.S. folk hero.
Sir Edward Victor Appleton
Appleton, Sir Edward Victor (1892–1965), English physicist who discovered the Appleton layer (now resolved as 2 layers, F1 and F2) of ionized gas molecules in the ionosphere.
Appolonius of Rhodes
Appolonius of Rhodes (3rd century B.C.), Greek poet, pupil of Callimachus, and later head of the library at Alexandria.
Appomattox Courthouse
Appomattox Courthouse, settlement in central Virginia where the Civil War ended with Confederate General Robert E.
legislative Apportionment
Apportionment, legislative, distribution of voters' representation in the lawmaking bodies.
Apprentice
Apprentice, person who works for an accomplished craftsperson to learn a trade.
Apricot
Apricot (Prunus armeniaca), tree of the rose family, native to China but grown throughout temperate regions; also, the orange-colored fruit of the tree.
April Fools' Day
April Fools' Day, or All Fools' Day, Apr. 1, the traditional day for practical jokes.
Lucius Apuleius
Apuleius, Lucius (c.A.D. 125–185), Latin writer.
Gulf of Aqaba
Aqaba, Gulf of, northeastern arm of the Red Sea, between the Sinai Peninsula and Saudi Arabia.
Aqua regia
Aqua regia (Latin, “royal water”), mixture of concentrated nitric and hydrochloric acids used since the Middle Ages to dissolve gold, the “royal metal,” and other substances that are difficult to get into solution.
Aquaculture
Aquaculture, controlled raising of marine animals and seaweed for harvest.
Aqualung
Aqualung See: Skin diving.
Aquamarine
Aquamarine, transparent blue or pale blue-green semiprecious stone, a variety of the mineral beryl.
Aquarium
Aquarium, tank, bowl, or pool in which aquatic animals and plants are kept.
Aqueduct
Aqueduct, artificial conduit for water.
Saint Thomas Aquinas
Aquinas, Saint Thomas (1225–74), Italian scholastic theologian and philosopher.
Corazon Aquino
Aquino, Corazon (1933–), first woman president of the Philippines (1986–92).
Arab
Arab, one whose language is Arabic and who identifies with Arab culture.
Arab-Israeli Wars
Arab-Israeli Wars, several conflicts between Israel and the Arabs. In 1948, when Israel was established as an independent state on what the Arabs regarded as Arab land, Egypt, Iraq, Transjordan (Jordan), Lebanon, and Syria attacked, but within a month Israel had occupied the greater part of Palestine. By July 1949, separate ceasefires were concluded with the Arab states. On Oct. 29, 1956, with the…
Arab League
Arab League, organization promoting economic, cultural, and political cooperation among Arab states, founded in 1945.
Arabesque
Arabesque, elaborate decorative style characterized by curved or intertwining shapes, with grotesque, animal, human, or symbolic forms and delicate foliage.
Arabia
Arabia See: Arabian Peninsula; Saudi Arabia.
Arabian Desert
Arabian Desert, one of the greatest desert regions in the world, comprising almost all of the deserts of the Arabian Peninsula in southwest Asia.
Arabian Nights
Arabian Nights, or The Thousand and One Nights, collection of ancient Persian, Indian, and Arabian folktales, written in Arabic and arranged in its present form during the early 16th century.
Arabian Peninsula
Arabian Peninsula, vast land, largely desert, in southwest Asia, surrounded by the Red Sea, the Arabian Sea, and the Persian Gulf.
Arabian Sea
Arabian Sea, northwestern sea of the Indian Ocean, between India and Arabia.
Arabic
Arabic, one of the Semitic languages.
Arabic numerals
Arabic numerals, also called Hindu-Arabic numerals, the most common symbols for numbers.
Arachne
Arachne, in Greek mythology, mortal so expert in weaving that she challenged Athena to a contest.
Arachnid
Arachnid, insectlike arthropod of the class Arachnida.
Yasir Arafat
Arafat, Yasir (1929– ), Palestinian political figure. After organizing the anti-Israel Al Fatah guerrillas in the 1950s, Arafat became chairman of the Palestine Liberation Organization (PLO) in 1969. In 1974 Arafat opened a debate on Palestine at the UN, where he led the first nongovernmental delegation to take part in a General Assembly plenary session. It is generally believed that Arafat…
Aragón
Aragón, historic region of northeastern Spain, stretching from the central Pyrenees to south of the Ebro River.
Aral Sea
Aral Sea, inland sea or saltwater lake covering 24,904 sq mi (64,501 sq km) in Kazakhstan and Uzbekistan.
Aramaic
Aramaic, Semitic language.
Arapaho
Arapaho, North American tribe of the Algonquian family.
Mount Ararat
Ararat, Mount, dormant volcanic mountain in eastern Turkey with 2 peaks, 16,950 ft (5,166 m) and 13,000 ft (3,962 m) high.
Araucanians
Araucanians, South American tribes famous for their resistance to the Spaniards, beginning with the 16th-century Spanish invasion of what is now central Chile.
Arawak
Arawak, group of often culturally distinct South American tribes, now living mostly in Brazil, the Guyanas, and Peru.
Arbitration
Arbitration, process for settling disputes in which the parties submit the controversy to an impartial arbitrator.
Arboretum
Arboretum, place in which trees and shrubs are cultivated for scientific or educational purposes.
Arc de Triomphe
Arc de Triomphe, Napoleon's triumphal arch in the Place Charles de Gaulle at the end of the Champs-Elysées, Paris.
electric Arc
Arc, electric See: Electric arc.
Joan of Arc
Arc, Joan of See: Joan of Arc, Saint.
Arc light
Arc light, device in which electrical current flowing between poles or electrodes produces the electric arc, yielding an intensely bright light.
Arcadia
Arcadia, ancient Greek region in central Peloponnesus, enclosed by mountains.
Eddie Arcaro
Arcaro, Eddie (George Edward Arcaro; 1916– ), U.S. jockey.
Arch
Arch, structural device to span openings and support loads.
Archaeopteryx
Archaeopteryx, prehistoric feathered reptile the size of a crow, with 2 claws representing the thumb and forefinger projecting from its wing and about 20 tail vertebrae.
Archangel
Archangel (pop. 419,000; Russian, Arkhangelsk), city in northwestern Russian Federation, near the mouth of the North Dvina River.
Archbishop
Archbishop, metropolitan bishop of the Roman Catholic, Anglican, or Eastern Orthodox church, or of the Lutheran churches of Finland and Sweden, having jurisdiction over the bishops of a church province, or archdiocese.
Archeoastronomy
Archeoastronomy, study of the astronomy of ancient peoples and its relation to other aspects of culture.
Archeology
Archeology, study of the past through identification and interpretation of the material remains of human cultures. Archeology uses the knowledge and techniques of such disciplines as anthropology, history, paleography, and philology. Its keystone is fieldwork. Archeology began in the early 18th century with excavations of Roman and other sites. The famous Rosetta Stone, which provided the key to E…
Archerfish
Archerfish, any of several species of Indo-Pacific fishes of the family Toxotidae with the ability to eject water from their mouths to knock insect prey to the surface; especially, Toxotes jaculator.
Archery
Archery, competitive and recreational sport, using bows and arrows.
Arches National Park
Arches National Park, 82,953 acres (33,571 hectares) in eastern Utah containing natural rock arches formed by weathering and erosion.
Archimedes
Archimedes (c.287–212 B.C.), Greek mathematician and physicist who spent most of his life in Syracuse, Sicily, where he was born.
Archipelago
Archipelago (Greek, “chief sea”), name originally applied to the Aegean Sea, which is studded with many small islands; by extension, any space of water interspersed with islands or the group of islands itself.
Architecture
Architecture, art or science of designing and building structures. While the beginnings of architecture are traceable to areas around the Nile, Euphrates, and Tigris rivers, the Greeks and Romans created the styles that we rely on today. Greek architecture used post-and-lintel construction: a rectangle formed by beams and columns. The Romans were the first to fully use the arch and to use concrete…
Archon
Archon, administrator of ancient Athens and other Greek city-states.
Arctic
Arctic, region north of the Arctic Circle (66°30' N); alternatively, regions north of the tree line. The Arctic comprises the Arctic Ocean, Greenland, Spitsbergen and other islands, extreme northern Europe, Siberia, Alaska, and northern Canada. The area's central feature is the Arctic Ocean, opening south into the North Atlantic Ocean and Bering Strait. The Arctic Ocean compri…
Arctic Circle
Arctic Circle, imaginary circle at 66 30′ N lat. roughly defining the tree line and marking the southernmost point of the polar area at which the midnight sun is seen.
Arctic fox
Arctic fox (Alopex lagopus), tundra dweller of the family Canidae.
Arctic Ocean
Arctic Ocean, the smallest ocean, centering on the North Pole and connecting with the Atlantic through the Greenland Sea and with the Pacific through the Bering Strait.
Arctic tern
Arctic tern (Sterna paradisaea), a coast-dwelling, long-distance migrant bird of the family Laridae.