• 0-9
  • a
  • b
  • c
  • d
  • e
  • f
  • g
  • h
  • i
  • j
  • k
  • l
  • m
  • n
  • o
  • p
  • q
  • r
  • s
  • t
  • u
  • v
  • w
  • x
  • y
  • z
  • point defect (crystallography)

    crystal defect: Point defects include the Frenkel type, the Schottky type, and the impurity type. The Frenkel defect involves a single ion, which is displaced from its normal lattice point and shifts to a nearby interstice, or space, between atoms in the lattice. In the Schottky defect,…

  • point estimation (statistics)

    Point estimation, in statistics, the process of finding an approximate value of some parameter—such as the mean (average)—of a population from random samples of the population. The accuracy of any particular approximation is not known precisely, though probabilistic statements concerning the

  • point flake (prehistoric tool)

    hand tool: The Mousterian flake tools: …two principal kinds of flakes, points and scrapers. The former are roughly triangular, with two trimmed or sharp edges meeting in a point, the base or butt of the triangle being thick and blunt. The side scrapers have a sharp edge in the long direction of the flake, with an…

  • Point Four Program (United States history)

    Point Four Program, U.S. policy of technical assistance and economic aid to underdeveloped countries, so named because it was the fourth point of President Harry S. Truman’s 1949 inaugural address. The first appropriations were made in 1950. The program was originally administered by a special

  • Point Given (racehorse)

    Gary Stevens: …in 2001, when he rode Point Given to a series of victories, most notably the Belmont and the Preakness. Stevens also raced in England and France, and arguably his most-notable win abroad was the 1999 Duke of Edinburgh Stakes at the British Royal Ascot.

  • point group (crystallography)

    Point group, in crystallography, listing of the ways in which the orientation of a crystal can be changed without seeming to change the positions of its atoms. These changes of orientation must involve just the point operations of rotation about an axis, reflection in a plane, inversion about a c

  • Point Kulon National Park (national park, Indonesia)

    Ujung Kulon National Park, national park on the island of Java, in the province of Banten, Indonesia. It is best known as the last refuge of the one-horned Javan rhinoceros. A remote area of low hills and plateaus, with small lagoons and coastal dunes, it occupies 475 square miles (1,229 square km)

  • Point Lenana (mountain peak, Kenya)

    East African mountains: Physiography: …closely followed in height by Lenana (16,355 feet).

  • point mutation (genetics)

    Point mutation, change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point

  • point of honour (dramatic theme)

    Lope de Vega: Works: …the “point of honour” (pundonor) that Vega commended as the best theme of all “since there are none but are strongly moved thereby.” This “point of honour” was a matter largely of convention, “honour” being equivalent, in a very limited and brittle sense, to social reputation; men were expected…

  • Point of No Return (novel by Marquand)

    John P. Marquand: …writing in his next novel, Point of No Return (1949), a painstakingly accurate social study of a New England town much like Newburyport. Two social types particularly important in the 1950s were depicted in Melville Goodwin, U.S.A. (1951), about a professional soldier, and Sincerely, Willis Wayde (1955), a sharply satiric…

  • point of order (law)

    parliamentary procedure: Rules of parliamentary procedure: Points of order may be made while another has the floor and when the question concerns the use of unparliamentary language. The question must be raised at the time the proceeding giving rise to the objection occurs.

  • Point of Order (American documentary film)

    motion picture: Newsreels and documentaries: Point of Order (1964), an American documentary film that ran successfully in motion-picture theatres, was made from television films of the U.S. Senate hearings on the charges and countercharges made by Sen. Joseph McCarthy and the U.S. Army.

  • Point of View (album by Wilson)

    Cassandra Wilson: Her first two solo albums, Point of View (1986) and Days Aweigh (1987), were heavily experimental, featuring psychedelic lyrics, electric instruments, and funk and reggae rhythms. Her third album, Blue Skies (1988), was more traditional; a collection of mostly jazz standards, it became her first popular success.

  • point of view (literature and film)

    Point of view, in literature, the vantage point from which a story is presented. A common point of view is the omniscient, in which, in the third person grammatically, the author presents a panoramic view of both the actions and the inner feelings of the characters; the author’s own comments on

  • point paper (textile design)

    textile: Woven fabrics: …conveys a composer’s ideas, so weave drafts or point paper plans communicate a textile designer’s directions for constructing woven fabrics. The draft is a plan on graph paper showing at least one repeat or weave unit of the fabric to be woven. This information enables the weaver or mill specialist…

  • Point Pelee National Park (national park, Ontario, Canada)

    Point Pelee National Park, park in southeastern Ontario, Canada, lying southeast of Leamington, at the western end of Lake Erie. Established in 1918, it occupies an area of 6 square miles (16 square km) and comprises a wedge-shaped sandspit jutting into the lake. It lies astride a major flyway of

  • Point Pleasant (West Virginia, United States)

    Point Pleasant, city, seat (1804) of Mason county, western West Virginia, U.S., on the Ohio River at the mouth of the Kanawha River, about 36 miles (58 km) northeast of Huntington. The settlement developed around Fort Blair, built in 1774, and was chartered in 1794. On October 10, 1774, the Battle

  • Point Pleasant, Battle of (United States history)

    Lewisburg: …Cornstalk that culminated in the Battle of Point Pleasant (October 10, 1774).

  • Point Reyes National Seashore (nature reserve, California, United States)

    Point Reyes National Seashore, rugged peninsula extending into the Pacific Ocean northwest of San Francisco, northern California, U.S. It fronts the Pacific Ocean to the west, Drakes Bay to the south, and Tomales Bay to the northeast; the latter bay extends inland about 13 miles (21 km) along the

  • Point Roberts (Washington, United States)

    Point Roberts, village, Whatcom county, northwestern Washington, U.S., near the Canadian border. It is located at the tip of a small peninsula (also called Point Roberts) that juts southward from British Columbia and is bisected by the international boundary, and it is surrounded on three sides by

  • point set (mathematics)

    mathematics: Riemann’s influence: …clear that some properties of point sets were important in the theory of integration, while others were not. (These other properties proved to be a vital part of the emerging subject of topology.) The properties of point sets that matter in integration have to do with the size of the…

  • Point, Fernand (French restauranteur)

    restaurant: French restaurants in the 20th century: …finest restaurant, was founded by Fernand Point and after his death, in 1955, retained its high standing under the direction of his widow, Madame “Mado” Point. Other leading French provincial restaurants have included the Troisgros in Roanne; the Paul Bocuse Restaurant near Lyon; the Auberge de l’Ill in Illhaeusern, Alsace;…

  • Point, The (Illinois, United States)

    Galena, city, seat (1827) of Jo Daviess county, northwestern Illinois, U.S. It lies along the Galena River (originally called Fever River), 4 miles (6 km) east of the Mississippi River and about 15 miles (25 km) southeast of Dubuque, Iowa. French explorers visited the region in the late 17th

  • Point, The (Internet-based program)

    Groupon: …Mason, a Web site called The Point that determined grassroots interest in and support for given causes. Users expressed support for a given cause via the site but were not asked to donate any time or money to a cause unless a certain amount of interest was achieved—the campaign’s “tipping…

  • point-contact transistor (electronics)

    transistor: Innovation at Bell Labs: …successful semiconductor amplifier, called the point-contact transistor, on December 16, 1947. Similar to the World War II crystal rectifiers, this weird-looking device had not one but two closely spaced metal wires jabbing into the surface of a semiconductor—in this case, germanium. The input signal on one of these wires (the…

  • point-count bidding (bridge game)

    bridge: Bidding systems: …method of valuation called the point count, an extension of similar methods proposed as early as 1904 but not previously made applicable to more than a fraction of the many hands a bridge player might hold. In other respects Goren’s system was similar to or identical with the methods advocated…

  • point-set topology (mathematics)

    Wacław Sierpiński: …be concentrated in set theory, point-set topology, the theory of real functions, and logic. Janiszewski died in 1920, but Sierpiński and Mazurkiewicz successfully saw the plan through. At the time it seemed a narrow and even risky choice of topics, but it proved highly fruitful, and a stream of fundamental…

  • point-source pollutant (water pollution)

    water pollution: Sources of pollution: Water pollutants come from either point sources or dispersed sources. A point source is a pipe or channel, such as those used for discharge from an industrial facility or a city sewerage system. A dispersed (or nonpoint) source is a very broad, unconfined area from which a variety of pollutants…

  • point-to-point (horse racing)

    Point-to-point, race run during the non-hunting season (February to May) by horses regularly ridden at fox hunts. The races originated in England in the second half of the 19th century as a way to keep hunters fit and were first called hunt races. Each hunt had one such race. All riders are

  • point-to-point (numerical control system)

    machine tool: Numerical control (NC): …into two basic types: (1) point-to-point and (2) continuous-path. Point-to-point systems, commonly used on machines that perform hole-machining and straight-line milling operations, are relatively simple to program and do not require the aid of a computer.

  • point-to-point microwave transmission

    telephone: Microwave link: …link in the form of point-to-point microwave systems. First employed in 1950, microwave transmission has the advantage of not requiring access to all contiguous land along the path of the system. Because microwave systems are line-of-sight media, radio towers must be spaced approximately every 42 km (25 miles) along the…

  • point-trick game

    card game: Classification: Point-trick games. To win the greatest value of point-scoring cards contained in tricks (skat, all fours, tarot games). Trick-avoidance games. To avoid winning penalty cards contained in tricks (hearts) or winning any tricks at all (misère). Trick-and-meld games. To make

  • Pointe Clairette (Gabon)

    Port-Gentil: …offshore at nearby Ozouri and Pointe Clairette in 1956 stimulated Port-Gentil’s commercial and industrial growth. A petroleum port was constructed, and an oil refinery and training school for the workers opened at Pointe Clairette. In addition, sawmilling and the production of plywood and veneer are also important. In addition to…

  • Pointe Courte, La (film by Varda [1954])

    Agnès Varda: …and photographer whose first film, La Pointe Courte (1954), was a precursor of the French New Wave movies of the 1960s.

  • Pointe de la Grande Casse (mountain, France)

    Savoy Alps: The highest peak is Pointe de la Grande Casse (12,631 feet [3,850 m]), a part of the Massif de la Vanoise and located in Vanoise National Park. Other subranges include Beaufortin, Bauges, Bornes, and Chablais. The Mont Blanc group sometimes is considered part of the Savoy Alps. Tourism and…

  • Pointe du Hoc (promontory, France)

    Omaha Beach: Pointe du Hoc: An ominous piece of land jutting into the English Channel, Pointe du Hoc provided an elevated vantage point from which huge German guns with a range of 25 km (15 miles) could deliver fire upon both Omaha Beach (7 km, or 4…

  • Pointe du Sable, Jean Baptiste (American pioneer)

    Jean-Baptist-Point Du Sable, black pioneer trader and founder of the settlement that later became the city of Chicago. Du Sable, whose French father had moved to Haiti and married a black woman there, is believed to have been a freeborn. At some time in the 1770s he went to the Great Lakes area of

  • pointe work (dance)

    dance criticism: The Enlightenment to Romanticism: …was developed in the 1820s—pointe work, or dancing on the tips of the toes. The exact origins are unknown, but early champions were the pioneering Romantic choreographer Felippo Taglioni and his daughter, the ballerina Marie Taglioni. The advent of pointe work was perfectly matched to the portrayal of the…

  • Pointe-à-Pitre (Guadeloupe)

    Pointe-à-Pitre, principal town and arrondissement of the French overseas département of Guadeloupe in the eastern Caribbean Sea. The town lies on the southwestern coast of Grande-Terre island, on the eastern shore of the Salée River, a channel that separates Grande-Terre from Basse-Terre, the

  • Pointe-Noire (Republic of the Congo)

    Pointe-Noire, town (commune), principal port of Congo (Brazzaville). It lies at the Atlantic coastal terminus of the Congo-Ocean Railway, 95 miles (150 km) north of the Congo River and 245 miles (394 km) west of Brazzaville, the national capital. Between 1950 and 1958 Pointe-Noire was the capital

  • pointed arch (construction)

    bridge: Stone arch bridges: ogival arch by concealing the angle at the crown and by starting the curves of the arches vertically in their springings from the piers. This elliptical shape of arch, in which the rise-to-span ratio was as low as 1:7, became known as basket-handled and has…

  • pointed minuscule (calligraphy)

    Insular script: …distinctive Insular script was the pointed minuscule that, by the 8th century, was beginning to attain the status of a book hand, as witness the Venerable Bede in his Historia ecclesiastica gentis Anglorum (“Ecclesiastical History of the English People”), written in about 731. Both Insular scripts were carried to the…

  • pointer (computing)

    computer science: Algorithms and complexity: …may be linked together by pointers (essentially, memory addresses stored with an item to indicate where the next item or items in the structure are found) so that the data can be organized in ways similar to those in which they will be accessed. The simplest such structure is called…

  • pointer (breed of dog)

    Pointer, highly regarded breed of sporting dog of hound, spaniel, and setter ancestry. The pointer derives its name from its assumption of a rigid posture in the direction of the quarry it has located. First recorded about 1650, in England, the pointer was originally used to point out hares for

  • Pointer Sisters, the (American vocal group)

    The Pointer Sisters, American vocal group that scored a string of pop, dance, and urban contemporary hits in the 1970s and ’80s. The sisters were Ruth Pointer (b. March 19, 1946, Oakland, California, U.S.), Anita Pointer (b. January 23, 1948, Oakland), Bonnie Pointer (b. July 11, 1950, Oakland),

  • Pointer, Anita (American musician)

    the Pointer Sisters: ), Anita Pointer (b. January 23, 1948, Oakland), Bonnie Pointer (b. July 11, 1950, Oakland), and June Pointer (b. November 30, 1953, Oakland—d. April 11, 2006, Santa Monica, California).

  • Pointer, Bonnie (American musician)

    the Pointer Sisters: January 23, 1948, Oakland), Bonnie Pointer (b. July 11, 1950, Oakland), and June Pointer (b. November 30, 1953, Oakland—d. April 11, 2006, Santa Monica, California).

  • pointer, German short-haired (breed of dog)

    pointer: The German shorthaired pointer is another sporting breed. Developed in Germany, it is an all-purpose dog that can track game as well as point and retrieve game in water. It is about the size of a pointer and has a short coat of solid liver colour…

  • pointer, German wirehaired (breed of dog)

    German wirehaired pointer, breed of sporting dog developed in mid-19th-century Germany as an all-purpose, all-weather hunting dog. It generally has a keen “nose” and a rugged constitution. It stands 22 to 26 inches (56 to 66 cm), weighs 50 to 70 pounds (23 to 32 kg), and has a deep chest and a

  • Pointer, June (American singer)

    June Pointer, American singer (born Nov. 30, 1953, Oakland, Calif.—died April 11, 2006, Santa Monica, Calif.), formed the successful pop group the Pointer Sisters with her three older siblings and served as leading vocalist on several of their most exuberant recordings. Pointer began performing i

  • Pointer, Ruth (American musician)

    the Pointer Sisters: The sisters were Ruth Pointer (b. March 19, 1946, Oakland, California, U.S.), Anita Pointer (b. January 23, 1948, Oakland), Bonnie Pointer (b. July 11, 1950, Oakland), and June Pointer (b. November 30, 1953, Oakland—d. April 11, 2006, Santa Monica, California).

  • pointillism (art)

    Pointillism, in painting, the practice of applying small strokes or dots of colour to a surface so that from a distance they visually blend together. The technique is associated with its inventor, Georges Seurat, and his student, Paul Signac, who both espoused Neo-Impressionism, a movement that

  • pointing (brickwork)

    Pointing, in building maintenance, the technique of repairing mortar joints between bricks or other masonry elements. When aging mortar joints crack and disintegrate, the defective mortar is removed by hand or power tool and replaced with fresh mortar, preferably of the same composition as the

  • pointing (sculpture)

    sculpture: Pointing: A sculpture can be reproduced by transposing measurements taken all over its surface to a copy. The process is made accurate and thorough by the use of a pointing machine, which is an arrangement of adjustable metal arms and pointers that are set to…

  • pointing (punctuation)

    punctuation: …was known in English as pointing; and the term punctuation, first recorded in the middle of the 16th century, was reserved for the insertion of vowel points (marks placed near consonants to indicate preceding or following vowels) in Hebrew texts. The two words exchanged meanings between 1650 and 1750.

  • pointing stick (input device)

    computer: Input devices: Pointing sticks, which are popular on many laptop systems, employ a technique that uses a pressure-sensitive resistor. As a user applies pressure to the stick, the resistor increases the flow of electricity, thereby signaling that movement has taken place. Most joysticks operate in a similar…

  • Pointless Nostalgic (album by Cullum)

    Jamie Cullum: His second album, Pointless Nostalgic, was recorded two years later by a jazz label, and it became such a favourite on British radio that the major labels Sony and Universal fought a bidding war to sign him.

  • Pointz Hall (work by Woolf)

    Virginia Woolf: Late work: …novel, Pointz Hall (later retitled Between the Acts), would include the play as a pageant performed by villagers and would convey the gentry’s varied reactions to it. As another holiday from Fry’s biography, Woolf returned to her own childhood with “A Sketch of the Past,” a memoir about her mixed…

  • Poiré, Emmanuel (Russian-French caricaturist)

    Caran d’Ache, caricaturist and illustrator whose line drawing was notable for its crisp, forceful simplicity. The name Caran d’Ache transliterates the Russian word for pencil. He was educated in Moscow but settled in Paris, where he gained great popularity as a contributor to several periodicals. H

  • Poiré, Jean-Gustave (French actor and playwright)

    Jean Poiret, French actor and playwright who wrote and starred in the original 1973 Paris production of La Cage aux folles, a farcical play about a gay couple that ran for more than 2,000 performances, inspired several films, and was adapted into a Tony Award-winning Broadway musical. In the early

  • Poire, La (cartoon by Philipon)

    Charles Philipon: La Poire became the common symbol of the king, and all Philipon’s artists used it in their caricatures. They were a notable group: he was able to attract and inspire the best talents in France. Honoré Daumier and Gustave Doré were the most famous, but…

  • Poiret, Jean (French actor and playwright)

    Jean Poiret, French actor and playwright who wrote and starred in the original 1973 Paris production of La Cage aux folles, a farcical play about a gay couple that ran for more than 2,000 performances, inspired several films, and was adapted into a Tony Award-winning Broadway musical. In the early

  • Poiret, Paul (French fashion designer)

    Paul Poiret, French couturier, the most fashionable dress designer of pre-World War I Paris. Poiret was particularly noted for his Neoclassical and Orientalist styles, for advocating the replacement of the corset with the brassiere, and for the introduction of the hobble skirt, a vertical

  • Poiret, Pierre (French mystic)

    Antoinette Bourignon: …collected (1679) by her disciple Pierre Poiret, who in the same year also wrote her biography.

  • Poirier, Louis (French author)

    Julien Gracq, (Louis Poirier), French writer (born July 27, 1910, Saint-Florent-le-Vieil, France—died Dec. 22, 2007, Angers, France), wrote a score of works, including novels, essays, journals, and the literary study André Breton: quelques aspects de l’écrivain. Gracq’s fiction displayed the strong

  • Poirier, Richard (American critic)

    American literature: Theory: … and Stanley Cavell and critic Richard Poirier found a native parallel to European theory in the philosophy of Emerson and the writings of pragmatists such as William James and John Dewey. Emulating Dewey and Irving Howe, Rorty emerged as a social critic in Achieving Our Country (1998) and Philosophy and…

  • Poirot, Hercule (fictional character)

    Hercule Poirot, fictional Belgian detective featured in a series of novels by Agatha Christie. Short, somewhat vain, with brilliantined hair and a waxed moustache, the aging bachelor Poirot enjoys his creature comforts. Relying on his “little grey cells” to solve crimes, Poirot is notably

  • poise (unit of measurement)

    chemical analysis: Viscosity measurements: …is measured in units of poises (dyne-seconds per square centimetre) or a subdivision of poises. For liquids viscosity is measured with an instrument called a viscometer, of which there are various types. One type of viscometer is a calibrated glass vessel. After inversion, the upper glass bulb is filled to…

  • Poiseuille flow (physics)

    fluid mechanics: Stresses in laminar motion: …which it refers is called Poiseuille flow.

  • Poiseuille’s equation (physics)

    Jean-Louis-Marie Poiseuille: …is also known as the Hagen-Poiseuille equation.

  • Poiseuille, Jean-Louis-Marie (French physician)

    Jean-Louis-Marie Poiseuille, French physician and physiologist who formulated a mathematical expression for the flow rate for the laminar (nonturbulent) flow of fluids in circular tubes. Discovered independently by Gotthilf Hagen, a German hydraulic engineer, this relation is also known as the

  • poison (biochemistry)

    Poison, in biochemistry, a substance, natural or synthetic, that causes damage to living tissues and has an injurious or fatal effect on the body, whether it is ingested, inhaled, or absorbed or injected through the skin. Although poisons have been the subject of practical lore since ancient times,

  • Poison (film by Haynes [1991])

    Todd Haynes: For his first full-length film, Poison (1991), Haynes intertwined three narratives inspired by the writings of Jean Genet. The film proved controversial, not simply because it explored sexual themes, including a story line about a gay man in prison, but because it received National Endowment for the Arts (NEA) funding…

  • poison (nuclear physics)

    Poison, in nuclear physics, any material that can easily capture neutrons without subsequently undergoing nuclear fission. Examples of poisons are the naturally occurring elements boron and cadmium and the fission products xenon-135 and samarium-149. In nuclear reactors, poisons act as parasitic

  • poison arrow frog (amphibian)

    Poison frog, (family Dendrobatidae), any of approximately 180 species of New World frogs characterized by the ability to produce extremely poisonous skin secretions. Poison frogs inhabit the forests of the New World tropics from Nicaragua to Peru and Brazil, and a few species are used by South

  • poison dart frog (amphibian)

    Poison frog, (family Dendrobatidae), any of approximately 180 species of New World frogs characterized by the ability to produce extremely poisonous skin secretions. Poison frogs inhabit the forests of the New World tropics from Nicaragua to Peru and Brazil, and a few species are used by South

  • poison elder (plant)

    Poison sumac, (Toxicodendron vernix), poisonous shrub or small tree of the cashew family (Anacardiaceae), native to swampy acidic soils of eastern North America. The clear sap, which blackens on exposure to air, contains urushiol and is extremely irritating to the skin for many people. The plant is

  • poison frog (amphibian)

    Poison frog, (family Dendrobatidae), any of approximately 180 species of New World frogs characterized by the ability to produce extremely poisonous skin secretions. Poison frogs inhabit the forests of the New World tropics from Nicaragua to Peru and Brazil, and a few species are used by South

  • poison gas (military science)

    chemical weapon: Properties of chemical weapons: Some poison gases, such as chlorine and hydrogen cyanide, enter the victim’s lungs during inhalation. On the other hand, nerve agent droplets might enter through the skin into the bloodstream and nervous system. Still other chemicals can be mixed with food in order to poison enemy…

  • poison gland (anatomy)

    integument: Fishes: Poison glands, which occur in the skin of many cartilaginous fishes and some bony fishes, are frequently associated with spines on the fins, tail, and gill covers. Photophores, light-emitting organs found especially in deep-sea forms, may be modified mucous glands. They may be used as…

  • poison guava (plant)

    Manchineel, (Hippomane mancinella), tree of the genus Hippomane, of the spurge family (Euphorbiaceae), that is famous for its poisonous fruits. The manchineel is native mostly to sandy beaches of the Caribbean and Gulf of Mexico. Its attractive, single or paired yellow-to-reddish, sweet-scented, a

  • poison hemlock (plant)

    Poison hemlock, (Conium maculatum), poisonous herbaceous plant of the parsley family (Apiaceae). Poison hemlock is native to Europe and North Africa and has been introduced to Asia, North America, and Australia. All parts of the plant contain the poisonous alkaloid coniine and are toxic to

  • Poison Ivy (film by Shea [1992])

    Drew Barrymore: …as the seductive teen in Poison Ivy (1992); the abused and violent Anita Minteer in Guncrazy (1992), for which she earned another Golden Globe nomination; and the lead in The Amy Fisher Story (1993), a television movie that was based on the true story of a teenage girl who shot…

  • Poison Ivy (song by Leiber and Stoller)

    the Coasters: …and “Charlie Brown” and “Poison Ivy” (both 1959). The Coasters alternated lead singers and featured clever arrangements, including amusing bass replies and tenor saxophone solos by King Curtis, who played a crucial role in creating Atlantic’s rhythm-and-blues sound. With further personnel changes they continued performing in “oldies” shows into…

  • poison ivy (plant)

    Poison ivy, (Toxicodendron radicans), poisonous vine or shrub of the cashew family (Anacardiaceae), native to eastern North America. Nearly all parts of the plant contain urushiol. When the plant is touched, the substance produces in many persons a severe, itchy, and painful inflammation of the

  • poison ivy family (plant family)

    Anacardiaceae, the sumac family of flowering plants (order Sapindales), with about 80 genera and about 870 species of evergreen or deciduous trees, shrubs, and woody vines. Most members of Anacardiaceae are native to tropical and subtropical areas of the world. A few species occur in temperate

  • poison oak (plant)

    Poison oak, either of two species of poisonous plants of the cashew family (Anacardiaceae), native to North America. Pacific, or western, poison oak (Toxicodendron diversilobum) is found in western North America, ranging from Baja California, Mexico, to British Columbia, Canada. Atlantic poison oak

  • poison parsnip (plant)

    Water hemlock, (genus Cicuta), genus of four species of poisonous plants in the parsley family (Apiaceae), common throughout the north temperate zone. Water hemlocks typically grow in wet, marshy places and are often confused with nonpoisonous members of the family, such as wild carrots or

  • poison ryegrass (plant)

    Darnel, noxious weed of the ryegrass (q.v.) genus

  • poison sumac (plant)

    Poison sumac, (Toxicodendron vernix), poisonous shrub or small tree of the cashew family (Anacardiaceae), native to swampy acidic soils of eastern North America. The clear sap, which blackens on exposure to air, contains urushiol and is extremely irritating to the skin for many people. The plant is

  • poison wind (wind)

    Simoom, extremely hot and dry local wind in Arabia and the Sahara. Its temperature often reaches 55 °C (about 130 °F), and the humidity of the air sometimes falls below 10 percent. It is caused by intensive ground heating under a cloudless sky. Simoom is an Arabic word that means “poison wind.” It

  • poison, catalyst (chemistry)

    Catalyst poison, substance that reduces the effectiveness of a catalyst in a chemical reaction. In theory, because catalysts are not consumed in chemical reactions, they can be used repeatedly over an indefinite period of time. In practice, however, poisons, which come from the reacting substances

  • poisoning (pathology)

    poison: Poisoning involves four elements: the poison, the poisoned organism, the injury to the cells, and the symptoms and signs or death. These four elements represent the cause, subject, effect, and consequence of poisoning. To initiate the poisoning, the organism is exposed to the toxic chemical.…

  • poisonous snake (reptile)

    mongoose: Natural history: …Herpestes, will attack and kill venomous snakes. They depend on speed and agility, darting at the head of the snake and cracking the skull with a powerful bite. Mongooses are bitten occasionally; however, they possess a glycoprotein that binds to proteins in snake venom, deactivating them and making them harmless.

  • Poisons, Affair of the (French history)

    Affair of the Poisons, one of the most sensational criminal cases of 17th-century France. In 1679 an inquiry revealed that nobles, prosperous bourgeois, and the common people alike had been resorting secretly to female fortune-tellers—at that time numerous in Paris—for drugs and poisons, for black

  • Poisonwood Bible, The (novel by Kingsolver)

    Barbara Kingsolver: With The Poisonwood Bible (1999), Kingsolver expanded her psychic and geographic territory, setting her story about the redemption of a missionary family in the Belgian Congo during the colony’s struggle for independence. In Prodigal Summer (2001) the intertwined lives of several characters living in Appalachia illuminate…

  • Poisson approximation

    probability theory: The Poisson approximation: The weak law of large numbers and the central limit theorem give information about the distribution of the proportion of successes in a large number of independent trials when the probability of success on each trial is p. In the mathematical formulation of…

  • Poisson distribution (statistics)

    Poisson distribution, in statistics, a distribution function useful for characterizing events with very low probabilities of occurrence within some definite time or space. The French mathematician Siméon-Denis Poisson developed his function in 1830 to describe the number of times a gambler would

  • Poisson law of large numbers (statistics)

    Poisson distribution, in statistics, a distribution function useful for characterizing events with very low probabilities of occurrence within some definite time or space. The French mathematician Siméon-Denis Poisson developed his function in 1830 to describe the number of times a gambler would

  • Your preference has been recorded
    Check out Britannica's new site for parents!
    Subscribe Today!