Encyclopaedia Britannica Online Shop

0-9

amnion ... Amu Darya

amnion: in reptiles, birds, and mammals, a membrane forming a fluid-filled cavity (the amniotic sac) that encloses the embryo. The amniotic sac and the fluid it contains are sometimes referred to ...
Amoco Corporation: American petroleum corporation that was founded in 1889 by the Standard Oil trust (see Standard Oil Company and Trust) to direct the refining and marketing of oil in the Midwestern ...
amoeba: any of the microscopic unicellular protozoans of the rhizopodan order Amoebida. The well-known type species, Amoeba proteus, is found on decaying bottom vegetation of freshwater streams and ponds. There are ...
Amoghasiddhi: (Sanskrit: "Unfailing Success"), in Mahayana and Vajrayana (Tantric) Buddhism, one of the five "self-born" Buddhas. See Dhyani-Buddha.
Amol: town, northern Iran, on the Harhaz River. The exact date of the founding of the town is unknown and enshrouded in legend, but it is certain that there has been ...
Amon: Egyptian deity who was revered as king of the gods.
Amontons, Guillaume: French physicist and inventor of scientific instruments, best known for his work on friction and temperature measurement.
amora: in ancient times, a Jewish scholar attached to one of several academies in Palestine (Tiberias, Sepphoris, Caesarea) or in Babylonia (Nehardea, Sura, Pumbedita). The amoraim collaborated in writing the Gemara, ...
Amorbach: city, Bavaria Land (state), southwestern Germany, in the Odenwald (wooded upland), southwest of Wurzburg. It originated around a Benedictine monastery in the 8th century and came under the jurisdiction of ...
Amorgos Island: island trending northeast-southwest in the Cyclades (Kikladhes) group of the Greek Aegean Islands. For the most part mountainous and narrow, it has an area of about 47 square miles (121 ...
Amorite: member of an ancient Semitic-speaking people who dominated the history of Mesopotamia, Syria, and Palestine from about 2000 to about 1600 BC. In the oldest cuneiform sources (c. 2400-c. 2000 ...
Amorite language: one of the most ancient of the archaic Semitic languages, distributed in an area that is now northern Syria. Amorite is known almost exclusively from glosses and names, and the ...
Amoroso Lima, Alceu: essayist, philosopher, and literary critic, a leading champion of the cause of intellectual freedom in Brazil. He was also an enthusiastic supporter of Modernismo, a Brazilian cultural movement of the ...
amorphous solid: any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Such solids include glass, plastic, and gel.
amortization: in finance, the systematic repayment of a debt; in accounting, the systematic writing off of some account over a period of years.
Amory, Thomas: British writer of Irish descent, best known for his extravagant "autobiography," The Life of John Buncle, 2 vol. (1756 and 1766), in which the hero marries seven wives in succession, ...
Amos: the first Hebrew prophet to have a biblical book named for him. He accurately foretold the destruction of the northern kingdom of Israel (although he did not specify Assyria as ...
Amos, Book of: the third of 12 Old Testament books that bear the names of the Minor Prophets, collected in one book under the Jewish canon titled The Twelve. Amos, a Judaean prophet ...
Amos, Valerie Ann, Baroness Amos of Brondesbury: British politician, the first woman of African descent to serve in a British cabinet and as leader of the House of Lords. She was educated at Townley Grammar School for ...
amosite: a variety of the silicate mineral cummingtonite, which is a source of asbestos (see cummingtonite).
Amoy: city and port on the coast of southern Fukien sheng (province), China. Amoy is situated on the southwest coast of Hsia-men Island at the mouth of the Chiu-lung River. Known ...
ampere: unit of electric current in the Systeme International d'Unites (SI), used by both scientists and technologists. Since 1948 the ampere has been defined as the constant current which, if maintained ...
Ampere's law: one of the basic relations between electricity and magnetism, stating quantitatively the relation of a magnetic field to the electric current or changing electric field that produces it. The law ...
Ampere, Andre-Marie: French physicist who founded and named the science of electrodynamics, now known as electromagnetism.
Ampere, Jean-Jacques: French historian and philologist who initiated important studies of the diverse cultural origins of western European languages and mythology. A world traveler, he wrote both scholarly works and Romantic poetry.
amphetamine: prototype of a series of synthetic drugs, all called amphetamines, that have pronounced stimulatory actions on the central nervous system. Amphetamine itself is a colourless liquid with an acrid taste ...
amphibian: any member of the class Amphibia, vertebrates distinguished by their ability to exploit both aquatic and terrestrial habitats. They include the frogs and toads, salamanders and newts, and caecilians. The ...
amphibious vehicle: device for transporting personnel and equipment, usually military, that can operate as a wheeled or tracked vehicle on land and as a boat in water. Two principal types appeared during ...
amphibious warfare: military operations characterized by attacks launched from the sea by naval and landing forces against hostile shores. The main form is the amphibious assault, which may be conducted for any ...
amphibole: any of a group of common rock-forming silicate minerals.
amphibole asbestos: a variety of the silicate mineral actinolite (q.v.).
amphibolite: a rock composed largely or dominantly of minerals of the amphibole group. The term has been applied to rocks of either igneous or metamorphic origin. In igneous rocks, the term ...
amphibolite facies: one of the major divisions of the mineral-facies classification of metamorphic rocks, the rocks of which formed under conditions of moderate to high temperatures (500° C, or about 950° F, ...
amphictyony: in ancient Greece, association of neighbouring states formed around a religious centre. The most important was the Amphictyonic League (Delphic Amphictyony). Originally composed of 12 tribes dwelling around Thermopylae, the ...
Amphion and Zethus: in Greek mythology, the twin sons of Zeus by Antiope. When children, they were left to die on Mount Cithaeron but were found and brought up by a shepherd. Amphion ...
amphioxus: any of certain members of the invertebrate subphylum Cephalochordata of the phylum Chordata. They are small marine animals found widely in the coastal waters of the warmer parts of the ...
amphipod: any member of the invertebrate order Amphipoda (class Crustacea) inhabiting all parts of the sea, lakes, rivers, sand beaches, caves, and moist (warm) habitats on many tropical islands. Marine amphipods ...
Amphipolis: ancient Greek city on the Strymon (Strimon) River about three miles from the Aegean Sea, in Macedonia. A strategic transportation centre, it controlled the bridge over the Strymon and the ...
Amphissa: agricultural centre, chief town of the eparkhia (eparchy) of Parnassus (Parnassos), capital of the nomos (department) of Fokis (Phocis), central Greece, at the northwestern ...
amphitheatre: freestanding building of round or, more often, oval shape with a central area, the arena, and seats concentrically placed around it. The word is Greek, meaning "theatre with seats on ...
Amphitherium: extinct genus of early mammals known as fossils from Middle Jurassic deposits (of 187 to 163 million years ago). Amphitherium is the earliest representative of the pantotheres, a group of ...
Amphitrite: in Greek mythology, the goddess of the sea, wife of the god Poseidon, and one of the 50 (or 100) daughters (the Nereids) of Nereus and Doris (the daughter of ...
Amphitryon: in Greek mythology, son of Alcaeus, king of Tiryns. Having accidentally killed his uncle Electryon, king of Mycenae, Amphitryon fled with Alcmene, Electryon's daughter, to Thebes, where he was cleansed ...
amphiuma: any of three species of North American salamanders belonging to the family Amphiumidae (order Urodela). Because they are long and slender and have inconspicuous legs, they are often mistaken for ...
amphora: one of the principal vessel shapes in Greek pottery, a two-handled pot with a neck narrower than the body. There are two types of amphora: the neck amphora, in which ...
amphora: ancient Roman unit of capacity for grain and liquid products equal to 48 sextarii and equivalent to about 27.84 litres (7.36 U.S. gallons). The term amphora was ...
amphoterism: in chemistry, reactivity of a substance with both acids and bases, acting as an acid in the presence of a base and as a base in the presence of an ...
ampicillin: drug used in the treatment of various infections, including otitis media (middle ear infection), sinusitis, and acute bacterial cystitis. Ampicillin (or alpha-aminobenzylpenicillin) is a semisynthetic penicillin, one of the first ...
amplifier: in electronics, device that responds to a small input signal (voltage, current, or power) and delivers a larger output signal that contains the essential waveform features of the input signal. ...
amplitude: in physics, the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of ...
amplitude modulation: variation of the amplitude of a carrier wave (commonly a radio wave) in accordance with the characteristics of a signal, such as a vocal or musical sound composed of audio-frequency ...
Ampthill: town ("parish"), Mid Bedfordshire district, administrative and historic county of Bedfordshire, England, 8 miles (13 km) south-southwest of Bedford. The Church of St. Andrew contains a monument to Richard Nicolls ...
Ampthill, Odo William Leopold Russell, 1st Baron: British diplomat, the first British ambassador to the German Empire (1871-84).
ampulla: a small narrow-necked, round-bodied vase for holding liquids, especially oil and perfumes. It was used in the ancient Mediterranean for toilet purposes and for anointing the bodies of the dead, ...
amputation: in medicine, removal of any part of the body. Commonly the term is restricted to mean surgical removal of a part of or an entire limb, either upper or lower ...
Amr ibn al-'As: the Arab conqueror of Egypt.
Amr ibn al-'As, Mosque of: earliest Islamic building in Egypt, erected in 641 by 'Amr ibn al-'As, the leader of an invading Arab army. The mosque was built in Al-Fustat, a city that grew out ...
Amr ibn Kulthum: pre-Islamic Arab poet whose qasidah ("ode") is one of the seven that comprise the celebrated anthology of pre-Islamic verse al-Mu'allaqat.
Amram bar Sheshna: head of the Talmudic academy at Sura, Babylonia, traditionally regarded as the first Jewish authority to write a complete domestic and synagogal liturgy for the year, the Siddur Rav Amram ...
Amratian culture: Egyptian predynastic cultural phase, centred in Upper Egypt, its type-site being al-'Amirah near Abydos in Qina muhafazah (governorate). Numerous sites, dating to about 3600 BC, have been excavated and reveal ...
Amravati: town, northeastern Maharashtra state, western India. It lies 85 miles (137 km) west of Nagpur. The town occupies an important position near passes through the hills that separate the cotton-growing ...
Amreli: town, southwestern Gujarat state, west-central India. The town lies on the Kathiawar Peninsula, 125 miles (200 km) southwest of Ahmadabad. Primarily a commercial centre, its industries include the manufacture of ...
Amritsar: city, northern Punjab state, northwestern India. It lies about 15 miles (25 km) east of the border with Pakistan. Amritsar is the largest and most important city in Punjab and ...
Amritsar, Massacre of: (April 13, 1919), incident in which British troops fired on a crowd of unarmed Indian protesters, killing a large number. It left a permanent scar on Indo-British relations and was ...
Amritsar, Treaty of: (April 25, 1809), pact concluded between Charles T. Metcalfe, representing the British East India Company, and Ranjit Singh, head of the Sikh kingdom of Punjab (Panjab); it settled Indo-Sikh relations ...
Amroha: town, northwestern Uttar Pradesh state, northern India, west-northwest of Moradabad town, on the Sot River. A marketplace for agricultural produce, its chief industries are hand-loom weaving, pottery making, and sugar ...
Amrouche, Jean: foremost poet of the earliest generation of French-speaking North African writers.
Amrouche, Marguerite Taos: Kabyle singer and writer.
Amsdorf, Nikolaus von: Protestant Reformer and major supporter of Martin Luther.
Amstelveen: gemeente (commune), Noordholland provincie, western Netherlands, near the Amstel River. Amstelveen (meaning "peat bog on the Amstel") was formerly a village in the municipality ...
Amsterdam: city, Montgomery county, eastern New York, U.S. It lies along the Mohawk River, 16 miles (26 km) northwest of Schenectady. Settled by Albert Veeder in 1783, it was known as ...
Amsterdam: city and port, western Netherlands, located on the IJsselmeer and connected to the North Sea. It is the capital and the principal commercial and financial centre of The Netherlands.
Amsterdam-Rhine Canal: waterway connecting the port of Amsterdam with the Lek River (via Utrecht) and the Waal River (at Tiel) in The Netherlands. Inaugurated in 1952, it has a total length of ...
Amstetten: town, Niederosterreich Bundesland (federal state), northeastern Austria. It is situated near the Ybbs River, northeast of Steyr. Recorded in 996 as a possession of the bishops of Passau, it was ...
Amtrak: federally supported corporation that operates nearly all intercity passenger trains in the United States. It was established by Congress in 1970 and assumed control of passenger service from the nation's ...
Amu Darya: one of the longest rivers of Central Asia. It is formed by the confluence of the Vakhsh and Panj (Pyandzh) rivers and flows west-northwest to its mouth on the southern ...