Anton Webern: Life and works: … (1908), and the choral canon Entflieht auf leichten Kähnen (1908). These still adhere to traditional tonality, but, with the Stefan George songs (1908–09), Webern entered the realm of music no longer based on a fixed tonal centre.

Wolfgang Amadeus Mozart: Vienna: the early years: …Entführung aus dem Serail (The Abduction from the Seraglio). (Joseph II currently required that German opera, rather than the traditional Italian, be given at the court theatre.) In the summer of 1781, rumours began to circulate, as far as Salzburg, that Mozart was contemplating marriage with the third of…

enthalpy, the sum of the internal energy and the product of the pressure and volume of a thermodynamic system. Enthalpy is an energy-like property or state function—it has the dimensions of energy (and is thus measured in units of joules or ergs), and its value is determined entirely by the

heat of formation, the amount of heat absorbed or evolved when one mole of a compound is formed from its constituent elements, each substance being in its normal physical state (gas, liquid, or solid). Usually the conditions at which the compound is formed are taken to be at a temperature of 25 °C

heat of reaction: …pressure is also designated the enthalpy of reaction, represented by the symbol ΔH. If the heat of reaction is positive, the reaction is said to be endothermic; if negative, exothermic.

arthritis: Spondyloarthropathies: Enthesitis, inflammation at the insertion of a tendon or ligament into bone, is a characteristic feature of spondyloarthropathy. Unlike rheumatoid arthritis, spondyloarthropathies are not associated with elevated levels of serum rheumatoid factor. Spondyloarthropathies occur most frequently in males and in individuals with a genetic variation…

Rajnikanth: … (1999), and the science-fiction thriller Enthiran (2010) and its sequel, 2.0 (2018); in the latter two movies he played both the robot Chitti Babu and its creator Dr. Vaseegaran. Rajnikanth’s acting style was characterized by unbridled exaggeration and pronounced mannerisms; his signature gesture—in which he deftly flipped a cigarette high…

biblical literature: Psalms: …city of Jerusalem, and the Enthronement Songs, which—though their number, setting, and interpretation have been the subject of much debate—acclaim Yahweh’s kingship over the whole world.

enthymeme, in syllogistic, or traditional, logic, name of a syllogistic argument that is incompletely stated. In the argument “All insects have six legs; therefore, all wasps have six legs,” the minor premise, “All wasps are insects,” is suppressed. Any one of the propositions may be omitted—even

universal: Universals and other entia non grata: ” As noted above, most objections to universals are based on the claim that universals, as compared with concrete physical things, are strange entities. Yet it is pointless to claim that universals are too strange to be countenanced if avoiding them commits one…

The Burial of the Count of Orgaz, large and luminous oil painting that was created about 1586 by the Greek-born artist El Greco. This painting, commissioned for and located in the church of Santo Tomé in Toledo, Spain, is widely considered to be El Greco’s masterpiece. El Greco was active in Rome

modern algebra: Structural axioms: …a set is called an integral domain. For example, the set of integers {…, −2, −1, 0, 1, 2, …} is a commutative ring with unity, but it is not a field, because axiom 10 fails. When only axiom 8 fails, a set is known as a division ring or…

Entisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Entisols are soils defined by the absence or near absence of horizons (layers) that clearly reflect soil-forming processes. Occupying just under 11 percent of the nonpolar continental land surface of the Earth, they are formed on surface

entitlement, generally, any government-provided or government-managed benefit or service to which some or all individuals are entitled by law. The term is also but less frequently applied to benefits provided by employers to employees unilaterally or as mandated by law or by contract (see fringe

famine: Entitlement failure: In the late 20th century the work of the Indian economist Amartya Sen led to a major reorientation in the study of famines. In works such as Poverty and Famines (1981), Sen challenged the prevailing “FAD hypothesis,” the assumption that total food-availability decline…

Robert Nozick: The entitlement theory of justice of Robert Nozick: Nozick’s vision of legitimate state power thus contrasts markedly with that of Rawls and his followers. Rawls argues that the state should have whatever powers are necessary to ensure that those citizens who are least well-off are as well-off…

myth: Demythologization of major religious traditions: Demythologization should be distinguished from secularization. Every living mythology must come to terms with the world in which it is transmitted and to that extent inevitably goes through processes of secularization. Demythologization, however, refers to the conscious efforts people make…

endoderm, the innermost of the three germ layers, or masses of cells (lying within ectoderm and mesoderm), which appears early in the development of an animal embryo. The endoderm subsequently gives rise to the epithelium (tissue that covers, or lines, a structure) of the pharynx, including the

entodiniomorph, any ciliated protozoan of the order Entodiniomorphida. They are harmless parasites in the rumen and intestines of cattle, horses, and other herbivores. Entodiniomorphs are common and extremely numerous: one cow may harbour 10 billion or more. The cells are irregularly shaped, and

entodiniomorph, any ciliated protozoan of the order Entodiniomorphida. They are harmless parasites in the rumen and intestines of cattle, horses, and other herbivores. Entodiniomorphs are common and extremely numerous: one cow may harbour 10 billion or more. The cells are irregularly shaped, and

Titian: Religious paintings: The Entombment is his first tragic masterpiece, where in a twilight setting the irrevocable finality of death and the despair of Christ’s followers are memorably evoked. The stately Presentation of the Virgin in the Temple, a very large canvas, reflects the splendour of Venetian Renaissance society…

Jacopo da Pontormo: …is best exemplified in the Entombment (Deposition from the Cross) (1525–28), painted soon after this for Santa Felicità, Florence.

Anne-Louis Girodet: …subjects in such works as The Entombment of Atala (1808). The latter picture, together with a windswept portrait of Chateaubriand meditating before the Roman Colosseum (1809), is most typical of his work.

entomology, branch of zoology dealing with the scientific study of insects. The Greek word entomon, meaning “notched,” refers to the segmented body plan of the insect. The zoological categories of genetics, taxonomy, morphology, physiology, behaviour, and ecology are included in this field of

entomophagy, the consumption of insects as a source of nutrition by humans. Entomophagy is practiced in most parts of the world, though it is especially common in the tropics, where more than 2,000 different species of insects are known to be consumed. Most species of insects that are eaten by

fungus: Annotated classification: Order Entomophthorales Primarily parasitic on insects, some may be saprotrophic in soil; coenocytic mycelium, may become septate; example genera include Entomophthora, Ballocephala, Conidiobolus, Entomophaga, and Neozygites. Subphylum Zoopagomycotina (incertae sedis) Endoparasitic

fungus: Annotated classification: Subphylum Entomophthoromycotina (incertae sedis) Pathogenic, saprotrophic, or parasitic; coenocytic or septate mycelium; rhizoids formed by some species; conidiophore branched or unbranched; conidia forcibly discharged; contains 1 order. Order Entomophthorales Primarily parasitic on insects, some may be

virus: Annotated classification: …are closely related antigenically, and Entomopoxvirinae, which infect arthropods. The Chordopoxvirinae are composed of groups called orthopoxviruses (vaccinia), parapoxviruses, avipoxviruses of birds, and many others that infect sheep, rabbits, and swine. Family Adenoviridae Nonenveloped virions of icosahedral symmetry, about 80 nm in diameter, and capsids

entoproct, any member of the phylum Entoprocta, a group of aquatic invertebrate animals composed of about 150 species and subdivided into four families. Entoprocts occur throughout the world, primarily in marine habitats, although one genus, Urnatella, is a freshwater form. Entoprocts may either

entoproct, any member of the phylum Entoprocta, a group of aquatic invertebrate animals composed of about 150 species and subdivided into four families. Entoprocts occur throughout the world, primarily in marine habitats, although one genus, Urnatella, is a freshwater form. Entoprocts may either

fungus: Annotated classification: Order Entorrhizales Pathogenic or saprotrophic; hyphae clamped; dolipore and parenthesome present; contains the only smut fungus that causes gall formation on roots; example genus is Entorrhiza. Kingdom Chromista Common microorganisms; includes important plant pathogens, such as the cause of potato

fungus: Annotated classification: Class Entorrhizomycetes Pathogenic or saprotrophic on roots of plants; contains 1 order. Order Entorrhizales Pathogenic or saprotrophic; hyphae clamped; dolipore and parenthesome present; contains the only smut fungus that causes gall formation on roots; example genus is Entorrhiza. Kingdom

Addis Ababa: Its immediate predecessor, Entoto, was situated on a high tableland and was found to be unsatisfactory because of extreme cold and an acute shortage of firewood. The empress Taitu, wife of Emperor Menilek II (reigned 1889–1913), persuaded the emperor to build a house near the hot springs at…

dipluran, (order Diplura), any of a group of about 800 species of small primitive wingless insects, considered by some entomologists to have features similar to ancestral insects. Diplurans have two appendages, or cerci, extending backward from the last of their abdominal segments, for which they

dipluran, (order Diplura), any of a group of about 800 species of small primitive wingless insects, considered by some entomologists to have features similar to ancestral insects. Diplurans have two appendages, or cerci, extending backward from the last of their abdominal segments, for which they

Martin Landau: …for a guest appearance on Entourage (2004–11).

René Clair: His next film, Entr’acte (1924), which was created to be shown between acts of a ballet by the modernist French composer Erik Satie, featured in its cast some of the most innovative artists of the day, including Satie and the Dadaist painters Marcel Duchamp, Francis Picabia, and Man…

ombre: The lowest bid, entrada, offers to do this after making any number of discards and drawing replacements from the stock. Vuelta is the same, except that the declarer must accept as trump the suit of the first card turned from stock. Highest is solo, in which the declarer…

museum: Entrance fees: Many museums charge entrance fees to help finance operations—even in some countries, such as the United Kingdom, that previously had a strong tradition of free entry to museums. Some museums charge admission fees only for major exhibitions. Others have introduced a system of…

entrapment, in law, instigation or inducement of a person into the commission of a crime by an officer of the law. Entrapment does not include situations in which the officer has not instigated the offense but merely provided the opportunity or occasion for its commission. Thus, the use of

Sean Connery: Rock (1996), Dragonheart (1996), and Entrapment (1999). Connery officially retired from acting following his appearance in the film adaptation (2003) of the comic-book series The League of Extraordinary Gentlemen, though he went on to perform various voice roles.

stagecraft: Renaissance costume: The progresses in England, entrées in France, and trionfi in Italy were based on the triumphal processions of the ancient world. The monarch or emperor was glorified as the hero, and the monarch’s entourage and vassals appeared in semiclassical grandeur. There were floats of allegorical figures and legions of…

Selena: Success as a solo artist and murder: … (1990; “Come with Me”) and Entre a Mi Mundo (1992; “Enter My World”). Her pop duet single, “Buenos Amigos” (“Good Friends”), with Salvadoran singer Álvaro Torres introduced her to a broader audience. In 1992 Selena married Chris Pérez, the lead guitarist of Los Dinos.

Minho, historical provincia, northwesternmost Portugal. It was originally called Entre Douro e Minho, the region between the Minho and Douro rivers. The area was occupied by both the Celts and the Romans, the former having left numerous ruins called castra, or hill forts. There is a narrow coastal

Entre Ríos, provincia (province), eastern Argentina. It is located between two rivers, the Paraná (west) and the Uruguay (east), the latter of which forms the Uruguayan border; the province’s name means “between rivers.” The city of Paraná, on the Paraná River, is the provincial capital. Entre Ríos

Ribeirão Prêto, city, northeastern São Paulo estado (state), southeastern Brazil. Situated in the Brazilian Highlands region at an elevation of 1,700 feet (520 metres) above sea level, it lies on the Prêto River, a tributary of the Pardo River. Founded in 1856 and formerly called Entre Rios and São

Nicaragua: Relief: …intricately dissected region includes the Cordillera Entre Ríos, on the Honduras border; the Cordilleras Isabelia and Dariense, in the north-central area; and the Huapí, Amerrique, and Yolaina mountains, in the southeast. The mountains are highest in the north, and Mogotón Peak (6,900 feet [2,103 metres]), in the Cordillera Entre Ríos,…

D’Entrecasteaux Islands: …named by the French navigator Bruni d’Entrecasteaux during his search for the missing explorer Jean-François de Galaup La Pérouse in 1793, the group was more accurately charted and individually named by Capt. John Moresby of HMS Basilisk in 1873. Copra is produced in fertile coastal patches.

entrechat, (probably from Italian intrecciare: “to weave,” or “to braid”), jump in ballet, beginning in the fifth position, during which the dancer crosses his straight legs at the lower calf. Numerous rapid crossings make the entrechat a spectacular jump. Numbers (trois, “three”; quatre, “four”;

Western theatre: Courtly entertainments: In France the entrées solennelles—entrance processions of great pomposity—were developed to a peak of elaborate ceremonial display. Aquatic pageantry also became popular in the 17th century, with the monarch surrounded by a collection of ornate barges, sea monsters, scallop shells, and ships.

entrelacement, a literary technique in which several simultaneous stories are interlaced in one larger narrative. This technique allows digression and presents opportunities for moral and ironic commentary while not disturbing the unity of the

thought: Obstacles to effective thinking: A mental set, or “entrenchment,” is a frame of mind involving a model that represents a problem, a problem context, or a procedure for problem solving. When problem solvers have an entrenched mental set, they fixate on a strategy that normally works well but does not…

Hong Kong: Economy: …as an international free port, entrepôt trade, mainly with China, flourished until 1951, when a United Nations embargo on trade with China and North Korea drastically curtailed it. This situation, combined with the need to export and with the availability of cheap labour, led to the establishment of competitive light…

economic growth: Entrepreneurship: This historical fact points to an element that has received little attention so far: the influence of entrepreneurship. If the allocation of resources changes during the course of growth and development, it does so under the leadership of an entrepreneurial class. The quality of…

profit: …market price and thus earn entrepreneurial profits. Secondly, changes in consumer tastes may cause revenues of some firms to increase, giving rise to what are often called windfall profits. The third type of profit is monopoly profit, which occurs when a firm restricts output so as to prevent prices from…

Building a business from the ground up—and assuming the risk.For many people, the word “entrepreneur” conjures up the archetypal image of a Silicon Valley start-up founder, shopping around the “next big idea” to deep-pocketed venture capitalists—sort of like what you’d see in an episode of Shark

economic growth: Entrepreneurship: This historical fact points to an element that has received little attention so far: the influence of entrepreneurship. If the allocation of resources changes during the course of growth and development, it does so under the leadership of an entrepreneurial class. The quality of…

entrepreneurship, the state of being an entrepreneur, or a person who organizes, manages, and assumes the risk of a business with the goal of generating economic value. The term is derived from the Old French verb entreprendre, “to undertake.” Entrepreneurship is one of the four factors of

Arnauld Family: …are preserved in the publication Entretien avec M. de Sacy (“Conversation with M. de Sacy”).

Denis Diderot: The Encyclopédie: …mention may be made of L’Entretien entre d’Alembert et Diderot (written 1769, published 1830; “Conversation Between d’Alembert and Diderot”), Le Rêve de d’Alembert (written 1769, published 1830; “D’Alembert’s Dream”), and the Eléments de physiologie (1774–80). In these works Diderot developed his materialist philosophy and arrived at startling intuitive insights into…

Francis Viélé-Griffin: …1890 Viélé-Griffin cofounded the review Les Entretiens politiques et littéraires (“Political and Literary Conversations”), in which appeared many of his essays calling for the liberation of verse from the strictures of traditional poetic form. He accomplished such liberation in his own poems through his pioneering use of vers libre (free…

Eugène-Emmanuel Viollet-le-Duc: Translated into English as Discourses on Architecture (1875), this work, containing information on the construction of iron skeletons enclosed by nonbearing masonry walls, especially influenced the late-19th-century architects of the Chicago school, particularly John W. Root. Other important writings by Viollet-le-Duc include L’Art russe (1877; “Russian Art”) and De…

Nicolas Malebranche: His Entretiens sur la métaphysique et sur la religion (1688; “Dialogues on Metaphysics and on Religion”), a series of 14 dialogues, has been called the best introduction to his system. His other writings include research into the nature of light and colour and studies in infinitesimal…

Bernard Le Bovier, sieur de Fontenelle: …la pluralité des mondes (1686; A Plurality of Worlds, 1688). These charming and sophisticated dialogues were more influential than any other work in securing acceptance of the Copernican system, still far from commanding universal support in 1686. Fontenelle’s basis of scientific documentation was meagre, and some of his figures were…

art criticism: Art criticism in the 17th century: Programmatic theory: …century with André Félibien’s 10-volume Entretiens sur les vies et sur les ouvrages des plus excellens peintres anciens et modernes (1666–88; “Conversations on the Most Excellent Painters, Ancient and Modern”). Like Vasari, Félibien presents what he regards as the proper principles of art, as well as an account of the…

Charles Van Lerberghe: …not issue a collection until Entrevisions. It consists of 64 poems, some written in free verse. Influenced by Henri Bergson’s theory of duration, these poems explore themes of transience and beauty through vague, indistinct images of the natural world. During this period Van Lerberghe traveled widely in Europe, eventually settling…

entropion, inward turning of the border (or margin) of the eyelid (usually the lower eyelids), occurring most often in elderly persons. It is commonly caused by age-related alterations in the fibrous and muscular support of the eyelids. The turning in of the lid margin allows the eyelashes to rub

information theory: Entropy: Shannon’s concept of entropy can now be taken up. Recall that the table Comparison of two encodings from M to S showed that the second encoding scheme would transmit an average of 5.7 characters from M per second. But suppose that, instead of the…

Thomas Pynchon: …stories, most notable are “Entropy” (1960), a neatly structured tale in which Pynchon first uses extensive technical language and scientific metaphors, and “The Secret Integration” (1964), a story in which Pynchon explores small-town bigotry and racism. The collection Slow Learner (1984) contains “The Secret Integration.”

entropy, the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work. Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system. The concept of entropy provides

coal mining: Ground control and roof support: …with the design of underground entries, their widths, the distance between the entries, and the number of entries that can be driven as a set. A hierarchy of entries exists in underground coal mines. Main entries are driven so as to divide the property into major areas; they usually serve…

Kapiti Island, uninhabited island at the northern entrance to Cook Strait, 5 miles (8 km) off the mouth of the Waikanae River, southwestern North Island, New Zealand. It is 9 square miles (23 square km) in area and may be part of a land bridge that once connected North and South islands. Generally

Western painting: Germany: …is also noticeable in Pforr’s “The Entry of the Emperor Rudolf of Habsburg into Basel in 1273” (c. 1809; Städelsches Kunstinstitut, Frankfurt am Main) and Schnorr’s “The Procession of the Three Magi” (1819; Museum of Fine Art, Leipzig). Alfred Rethel, a late arrival, however, manages to avoid such an effect…

decision problem, for a class of questions in mathematics and formal logic, the problem of finding, after choosing any question of the class, an algorithm or repetitive procedure that will yield a definite answer, “yes” or “no,” to that question. The method consists of performing successively a

encyclopaedia: The 19th century: …which became known as “Granat” after the Granat Russian Bibliographical Institute that produced it. A later edition (1910–48) of “Granat,” in 58 volumes, was not exported from the Soviet Union. Modeled on the Britannica, this edition contained many important articles, such as Lenin’s contribution on “Marx” and on “The…

Eduard Suess: …published a small book entitled Die Enstehung der Alpen (“The Origin of the Alps”). In it he argued that horizontal movements of the lithosphere (the Earth’s rocky outer shell), rather than vertical uplift, played the dominant role in creating mountain ranges by folding and thrust faulting. Suess assumed that volcanism…

Alfred Wegener: …der Kontinente und Ozeane (The Origin of Continents and Oceans). He searched the scientific literature for geological and paleontological evidence that would buttress his theory, and he was able to point to many closely related fossil organisms and similar rock strata that occurred on widely separated continents, particularly those…

Friedrich Meinecke: Die Entstehung des Historismus (1936; Historism) traces the rise of historicism from Giambattista Vico to Leopold von Ranke. Meinecke’s emphasis on the importance of the private concerns of individuals implied a clear opposition to the Nazis, who valued a person only as an instrument of the state’s aims.…

Enets, an indigenous Arctic people who traditionally resided on the east bank of the lower Yenisey River of Russia. They numbered about 300 in the Russian census of 2002. The Enets live in the Arctic tundra, a region of permafrost, and are divided into two major groups, the so-called Tundra Enets

history of Mesopotamia: The Sumerians to the end of the Early Dynastic period: …the ruler’s special title was en. In later periods this word (etymology unknown), which is also found in divine names such as Enlil and Enki, has a predominantly religious connotation that is translated, for want of a better designation, as “en-priest, en-priestess.” En, as the ruler’s title, is encountered in…

Julius Meier-Graefe: …Entwickelungsgeschichte der modernen Kunst (1904; Modern Art: Being a Contribution to a New System of Aesthetics), a study now widely regarded as establishing and codifying current assumptions of the movement’s stylistic evolution.

bildungsroman, class of novel that depicts and explores the manner in which the protagonist develops morally and psychologically. The German word Bildungsroman means “novel of education” or “novel of formation.” The folklore tale of the dunce who goes out into the world seeking adventure and learns

the Who: March 1, 1944, London), John Entwistle (b. October 9, 1944, London—d. June 27, 2002, Las Vegas, Nevada, U.S.), and Keith Moon (b. August 23, 1946, London—d. September 7, 1978, London). Moon was replaced by Kenney Jones (b. September 16, 1948, London).

the Who: March 1, 1944, London), John Entwistle (b. October 9, 1944, London—d. June 27, 2002, Las Vegas, Nevada, U.S.), and Keith Moon (b. August 23, 1946, London—d. September 7, 1978, London). Moon was replaced by Kenney Jones (b. September 16, 1948, London).

Johann Bernhard Fischer von Erlach: Foreign travels and change of style. of Johann Bernhard Fischer von Erlach: …a great history of architecture, Entwurf einer historischen Architektur. His book, which reveals the wide range of his learning, was the first comparative history of the architecture of all times and all nations; it included significant specimens of Egyptian, Persian, Greek, Roman, Muslim, Indian, and Chinese architecture, illustrated by engravings…

fungus: Annotated classification: Order Entylomatales Parasitic and pathogenic on plants, causing rice leaf smut and dahlia smut; ballistospore-forming; example genera include Entyloma and Tilletiopsis. Order Exobasidiales Parasitic and pathogenic on vascular plants; lacking basidiocarps; basidia produced in a layer on the surface of parasitized plants; example genera

Enugu, town, capital of Enugu state, southeastern Nigeria, located at the foot of the Udi Plateau. Enugu is on the railroad from Port Harcourt, 150 miles (240 km) south-southwest, and at the intersection of roads from Aba, Onitsha, and Abakaliki. The town owes its existence to the discovery of coal

Enugu, state, south-central Nigeria. It was created in 1991 from the eastern two-thirds of Anambra state. Enugu is bounded by the states of Kogi and Benue to the north, Ebonyi to the east, Abia to the south, and Anambra to the west. It includes most of the Udi-Nsukka Plateau, which rises to more

astrology: Astral omens in the ancient Middle East: …time when the cuneiform text Enūma Anu Enlil, devoted to celestial omina, was initiated. The final collection and codification of this series, however, was not accomplished before the beginning of the 1st millennium bc. But the tablets that have survived—mainly from the Assyrian library of King Ashurbanipal (7th century bc)—indicate…

Enuma elish, ancient Mesopotamian creation epic that tells the tale of Marduk, the chief god of the city of Babylon. He defeats the elder goddess Tiamat and brings order to chaos and thus becomes the Lord of the Gods of Heaven and Earth. The title of the poem comes from the first line of the work

combinatorics: Problems of enumeration: An ordered set a1, a2,…, ar of r distinct objects selected from a set of n objects is called a permutation of

bibliography: Descriptive bibliography: The primary purpose of descriptive bibliography is to organize detailed information culled from a mass of materials in a systematic way so that others can have access to useful information. In the earliest bibliographies, the organizing principle was simply that of compiling all…

enuresis, elimination disorder characterized by four factors: the repeated voluntary or involuntary voiding of urine during the day or night into bedding or clothing; two or more occurrences per month for a child between the ages of five and six (one or more for older children); chronological age

envelope, in poetry, a device in which a line or a stanza is repeated so as to enclose a section of verse, as in Sir Thomas Wyatt’s “Is it

balloon flight: Elements of balloon flight: …for the actual balloon, or envelope. Cotton, nylon, and polyester are common for the envelopes of hot-air balloons. Cotton, having a poor weight-to-strength ratio, is only favoured for carnival “smoke” balloons. Although gas balloons have sometimes used rubberized cotton, modern sport gas balloons use urethane-coated nylon. Balloons for high-altitude research…

Huygens’ principle: …front and is called the envelope of the wavelets. If a medium is homogeneous and has the same properties throughout (i.e., is isotropic), permitting light or sound to travel with the same speed regardless of its direction of propagation, the three-dimensional envelope of a point source will be spherical; otherwise,…

envelope, in musical sound, the attack, sustain, and decay of a sound. Attack transients consist of changes occurring before the sound reaches its steady-state intensity. Sustain refers to the steady state of a sound at its maximum intensity, and decay is the rate at which it fades to silence. In

envelope, in mathematics, a curve that is tangential to each one of a family of curves in a plane or, in three dimensions, a surface that is tangent to each one of a family of surfaces. For example, two parallel lines are the envelope of the family of circles of the same radius having centres on a

motion-picture technology: Light sources: tungsten-halogen lamps with quartz envelopes came into wide use. The halogen compound is included inside the envelope, and its purpose is to combine with the tungsten evaporated from the hot filament. This forms a compound that is electrically attracted back to the tungsten filament. It thus prevents the evaporated…