short verse composition, so constructed that the initial letters of the lines, taken consecutively, form words. The term is derived from the Greek words akros, "at the end," and stichos,"line," or "verse."
in architecture, decorative pedestal for an ornament or statue placed atop the pediment of a Greek temple; the term has also been extended to refer to the statue or ornament that stands on the pedestal. Originally a petal-shaped ornament with ...
any of a class of synthetic plastics, resins, and oils used to manufacture many products. By varying the starting reagents and the process of forming, a material may be produced that is hard and transparent, soft and resilient, or a ...
painting executed in the medium of synthetic acrylic resins. Acrylics dry rapidly, serve as a vehicle for any kind of pigment, and are capable of giving both the transparent brilliance of watercolour and the density of oil paint. They are ...
plain, hanging, weight-driven wall clock with a large wooden, painted or lacquered dial. The term Act of Parliament clock was applied incorrectly to these timepieces, which were thought to have been displayed by innkeepers to save their customers from paying ...
(Latin: "Acts"), in ancient Rome, minutes of public business and gazette of political and social events. They were in two forms: Acta Senatus and Acta diurna.
in Greek mythology, son of the god Aristaeus and Autonoe (daughter of Cadmus, the founder of Thebes in Boeotia); he was a Boeotian hero and hunter. According to Ovid's Metamorphoses, Actaeon accidentally saw Artemis (goddess of wild animals, vegetation, and ...
protein that is an important contributor to the contractile property of muscle and other cells. It exists in two forms: G-actin (monomeric globular actin) and F-actin (polymeric fibrous actin), the form involved in muscle contraction. In muscle, two long strands ...
the performing art in which movement, gesture, and intonation are used to realize a fictional character for the stage, for motion pictures, or for television.
any of a series of 15 consecutive chemical elements in the periodic table from actinium to lawrencium (atomic numbers 89-103). As a group they are significant largely because of their radioactivity. Although several members of the group, including uranium (the ...
(Ac), radioactive chemical element, in Group IIIb of the periodic table, atomic number 89. Actinium was discovered (1899) by Andre-Louis Debierne in pitchblende residues left after Pierre and Marie Curie had extracted radium and was also discovered (1902) independently by ...
an amphibole mineral in the tremolite-actinolite-ferrotremolite series of calcium, magnesium, and iron silicates. The minerals in this series are abundant in regionally metamorphosed rocks, such as schists. Tremolite may weather to talc, and both tremolite and actinolite may alter to ...
in chemistry, a substance or a mixture of substances that reacts through the action of light and that, because of the easily determined quantitative relationship between the extent of the reaction and the energy of the absorbed light, is used ...
any member of a heterogeneous group of gram-positive, generally anaerobic bacteria noted for a filamentous and branching growth pattern that results, in most forms, in an extensive colony, or mycelium. The mycelium in some species may break apart to form ...
a noncontagious bacterial infection of humans and cattle that is caused by two anaerobic species of the genus Actinomyces. The disease is characterized by multiple painful, hard swellings filled with pus, most often seen on the face, neck, chest, and ...
any parasitic microorganism of the class Actinomyxidia (Actinosporea), phylum Myxosporidia (Myxospora). It inhabits the alimentary canal of certain aquatic worms. The characteristic spores develop in the host's gut after the union of large and small gametes. The spores contain three ...
in theoretical physics, an abstract quantity that describes the overall motion of a physical system. Motion, in physics, may be described from at least two points of view: the close-up view and the panoramic view. The close-up view involves an ...
(French: "French Action"), influential right-wing antirepublican group in France during the first 40 years of the 20th century. Action Francaise was also the name of a daily newspaper (published from March 21, 1908, to Aug. 24, 1944) that expressed the ...
direct, instinctual, and highly dynamic kind of art that involves the spontaneous application of vigorous, sweeping brushstrokes and the chance effects of dripping and spilling paint onto the canvas. The term was coined by the American art critic Harold Rosenberg ...
the brief (about one-thousandth of a second) reversal of electric polarization of the membrane of a nerve cell (neuron) or muscle cell. In the neuron an action potential produces the nerve impulse, and in the muscle cell it produces the ...
(September 2, 31 BC), naval battle off a promontory in the north of Acarnania, on the western coast of Greece, where Octavian (known as the emperor Augustus after 27 BC), by his decisive victory over Mark Antony, became the undisputed ...
sewage-treatment process in which sludge, the accumulated, bacteria-rich deposits of settling tanks and basins, is seeded into incoming waste water and the mixture agitated for several hours in the presence of an ample air supply. Suspended solids and many organic ...
in psychology, the stimulation of the cerebral cortex into a state of general wakefulness, or attention. Activation proceeds from various portions of the brain, but primarily from the reticular formation, the nerve network in the midbrain that monitors ingoing and ...
in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport. In terms of the transition-state theory (q.v.), the activation energy is the ...
in radioactive-decay processes, the number of disintegrations per second, or the number of unstable atomic nuclei that decay per second in a given sample. Activity is determined by counting, with the aid of radiation detectors and electronic circuits, the number ...
in chemistry, the ratio of the chemical activity of any substance to its molar concentration. The measured concentration of a substance may not be an accurate indicator of its chemical effectiveness, as represented by the equation for a particular reaction, ...
amendment to the Brazilian constitution of 1824 that abolished some of that charter's extremely centralist and authoritarian aspects. It was enacted as a concession to federalists and republicans who threatened to sunder the nation.
English Liberal historian and moralist, the first great modern philosopher of resistance to the evil state, whether its form be authoritarian, democratic, or socialist. A comment that he wrote in a letter, "Power tends to corrupt, and absolute power corrupts ...
commander of the naval forces of Tuscany and then of Naples who as prime minister of Naples allied that kingdom with England and Austria in the period of the French Revolution.
method of theatrical production dominant in England and the U.S. in the 19th century, consisting of a permanent company formed by a leading actor who chose his own plays, took a leading role in them, and handled business and financial ...
prestigious professional actors' workshop in New York City whose members have been among the most influential performers in American theatre and film since World War II. It is one of the leading centres for the Stanislavsky method of dramatic training. ...
fifth book of the New Testament, a valuable history of the early Christian church. Acts was written in Greek, presumably by the Evangelist Luke, whose gospel concludes where Acts begins, namely, with Christ's Ascension into heaven. Acts was apparently written ...
one who calculates insurance risks and premiums. Actuaries compute the probability of the occurrence of various contingencies of human life, such as birth, marriage, sickness, unemployment, accidents, retirement, and death. They also evaluate the hazards of property damage or loss ...
American vocalist, songwriter, and fiddle player, called the "King of Country Music," who in the mid-1930s reasserted the mournful musical traditions of Southeastern rural whites and became a national radio star on the "Grand Ole Opry" broadcasts.
ancient Chinese medical technique for relieving pain, curing disease, and improving general health. It was devised before 2500 BC in China and by the late 20th century was used in many other areas of the world. Acupuncture consists of the ...
any tax imposed on the basis of the monetary value of the taxed item. Literally the term means "according to value." Traditionally, most customs and excises had "specific" rates; the tax base was defined in terms of physical units such ...
city, seat (1907) of Pontotoc county, south-central Oklahoma, U.S. It lies along Clear Boggy Creek, south of the Canadian River, and was named for the daughter of the first postmaster, William J. Reed, who built a log store there in ...
ivory carvings and a group of about 10 illuminated manuscripts, dating from the last quarter of the 8th century, the earliest examples of the art of the Court School of Charlemagne. The group is named after a Gospel book (c. ...
ancient Sumerian city located south of Nippur (modern Niffer or Nuffar), Iraq. Excavations (1903-04) carried out by the American archaeologist Edgar James Banks revealed buildings dating from as early as the prehistoric period and as late as the reign of ...
Islamic concept that became a literary genre distinguished by its broad humanitarian concerns; it developed during the brilliant height of 'Abbasid culture in the 9th century and continued through the Muslim Middle Ages.
weather god of the Babylonian and Assyrian pantheon. The name Adad may have been brought into Mesopotamia toward the end of the 3rd millennium BC by Western (Amorite) Semites. His Sumerian equivalent was Ishkur and the West Semitic was Hadad.
a saying, often in metaphoric form, that embodies a common observation, such as "If the shoe fits, wear it,'' "Out of the frying pan, into the fire,'' or "Early to bed, early to rise, makes a man healthy, wealthy, and ...
(Arabic: "custom"), in Islamic law, a local custom that is given a particular consideration by judicial authorities even when it conflicts with some principle of canon law (Shari'ah); in Indonesia it is known as adat, in North Africa it is ...
(1908), case in which the U.S. Supreme Court upheld "yellow dog" contracts forbidding workers from joining labour unions. William Adair of the Louisville and Nashville Railroad fired O.B. Coppage for belonging to a labour union, an action in direct violation ...
Scottish surveyor and cartographer whose maps established a standard of excellence for his time and probably inspired the early 18th-century surveys of Scotland. Between 1680 and 1686 he completed maps of the counties adjoining the River Forth as well as ...
historic Islamic state of eastern Africa, in the Danakil-Somali region southwest of the Gulf of Aden, with its capital at Harer (now in Ethiopia). Its rivalry with Christian Ethiopia began in the 14th century with minor border raids and skirmishes. ...
archbishop of Reims who, by declaring the Frankish crown to be elective rather than hereditary, paved the way for the accession of Hugh Capet in place of the Carolingian claimant, Charles, Duke of Lower Lorraine.
Lombard king of Italy who shared the throne for 11 years with his father, Berengar II, and after Berengar's exile continued his father's struggle against the German king and Holy Roman emperor Otto I.
