orchid: Natural history: …are pollinated by the wasps Trielis and Gorytes, and the bee Eucera induce the insects to attempt copulation with the apex of the lip. Those orchids pollinated by Andrena appear, for the most part, to stimulate the bee to reverse its position and copulate with the base of the lip.…

Charles I: Conflict with Parliament: …conciliatory attitude—he agreed to the Triennial Act that ensured the meeting of Parliament once every three years—but expressed his resolve to save Strafford, to whom he promised protection. He was unsuccessful even in this, however. Strafford was beheaded on May 12, 1641.

United Kingdom: The revolution settlement: A Triennial Act (1694) reestablished the principle of regular parliamentary sessions.

Adoniram Judson: …what is now called the American Baptist Foreign Mission Society. When the British East India Company opposed them in India, the Judsons relocated to Rangoon in 1813; there Judson mastered the Burmese language and literature and learned Pāli, the Buddhist canonical language.

Trento, city, Trentino–Alto Adige/Südtirol regione (region), northern Italy. It lies along the Adige River, south of Bolzano. Trento was founded, according to the classical savant Pliny the Elder and the geographer Strabo of Amaseia, by the Raetians, and it became a Roman colony and military base

Trier, city, Rhineland-Palatinate Land (state), southwestern Germany. It lies on the right bank of the Moselle (Mosel) River, surrounded by the foothills of the Eifel, Hunsrück, and Mosel mountains, just east of the border with Luxembourg. A shrine of the Treveri, a Germanic tribe, existed at the

Danish literature: Postwar literary trends: Dea Trier Mørch, a politically committed author and a member of the Røde Mor (“Red Mother”) artist collective, scored her greatest success with Vinterbørn (1976; Winter’s Child), a sensitive novel about women from various social circumstances at a maternity hospital. It gave voice to Trier…

Lars von Trier is a Danish film director and cofounder of the Dogme 95 movement, whose films are known for their bleak worldview and controversial subject matter. Von Trier attended the National Film School of Denmark, graduating in 1983. He was born Lars Trier, but while in school he added the

Trieste, city and capital of Friuli-Venezia Giulia regione and of Trieste provincia, northeastern Italy, located on the Gulf of Trieste at the northeastern corner of the Adriatic Sea 90 miles (145 km) east of Venice. It was under Roman control by about 177 bce; Julius Caesar made it a colony and

Trieste, city and capital of Friuli-Venezia Giulia regione and of Trieste provincia, northeastern Italy, located on the Gulf of Trieste at the northeastern corner of the Adriatic Sea 90 miles (145 km) east of Venice. It was under Roman control by about 177 bce; Julius Caesar made it a colony and

Trieste, bathyscaphe (q.v.) launched by Auguste Piccard in

20th-century international relations: Peace treaties and territorial agreements: Trieste was contested by Italy and Yugoslavia and remained under Western occupation until 1954. The major change affected Poland, which was figuratively picked up and moved some 150 miles to the west. This meant that large portions of eastern Germany came under Polish administration, while…

Yap Trench: …of the Pacific Ocean, the Trieste Depth (36,201 feet [11,034 m]), occurs near the intersection of the Mariana and Yap trenches.

Naples: The Castel Nuovo: Immediately south, on Piazza Trieste e Trento, the 17th-century church of San Ferdinando has traditionally given the Stabat Mater of Giovanni Battista Pergolesi—composed in 1736 for this confraternity—during Easter Week.

Trieste, bathyscaphe (q.v.) launched by Auguste Piccard in

Free Territory of Trieste, former region, western Istria, southern Europe, surrounding and including the city of Trieste. It was occupied by Yugoslavia in 1945. The United Nations established it as a free territory in 1947. It was divided for administrative purposes into two zones: Zone A in the

coordination compound: Coordination compounds in industry: …titanium trichloride, or TiCl3, and triethylaluminum, or Al(C2H5)3—bring about the polymerizations of organic compounds with carbon-carbon double bonds under mild conditions to form polymers of high molecular weight and highly ordered (stereoregular) structures. Certain of these polymers are of great commercial importance because they are used to make many kinds…

Nam Viet: His son Chao T’o (Trieu Da) expanded the new kingdom southward, incorporating the Red River delta and the area as far south as Da Nang.

horse racing: Wagers: …but not in order), and trifecta (win, place, and show winners in order in one race). Other specialty wagers, sometimes offering extremely high payouts, require the bettor to select multiple trifectas, the winners of several races, or the first four horses in one race.

Trifid Nebula, (catalog numbers NGC 6514 and M 20), bright, diffuse nebula in the constellation Sagittarius, lying several thousand light-years from the Earth. It was discovered by the French astronomer Legentil de La Galaisière before 1750 and named by the English astronomer Sir John Herschel for

trifle, a common English dessert traditionally consisting of sponge cake soaked in brandy, sherry, or white wine that is layered with custard, fruit, or jam and then topped with whipped cream and slivered almonds or glacé cherries. It is typically served in glass dessert cups, revealing its

Fabales: Classification of Fabaceae: …those with three leaflets (trifoliolate) are common—e.g., beans and soybeans. Trifoliolate leaves rarely occur in the other subfamilies. The large genus of Lupinus (lupines) generally has 5 to 11 (occasionally up to 15) palmate leaves. The leaves of clovers are most commonly palmately trifoliolate, as are those of Baptisia.…

clover, (genus Trifolium), genus of about 300 annual and perennial species in the pea family (Fabaceae). Clovers occur in most temperate and subtropical regions of the world, except Southeast Asia and Australia; cultivated species have become naturalized in temperate regions worldwide. The plants

shamrock: White clover (Trifolium repens) and suckling clover (T. dubium) are both native to the British Isles and have been variously identified as the emblematic shamrock; the plants are members of the pea family (Fabaceae). Of commercial importance is wood sorrel (Oxalis acetosella) of the family Oxalidaceae. The plant is found…

clover: repens), and alsike clover (T. hybridum). Red clover, a biennial, or short-lived perennial, bears an oval purplish flower head about 2.5 cm (1 inch) in diameter. White clover, a low creeping perennial, is often used in lawn-grass mixtures and bears a white flower head often tinged with…

clover: …most important agricultural species are red clover (Trifolium pratense), white clover (T. repens), and alsike clover (T. hybridum). Red clover, a biennial, or short-lived perennial, bears an oval purplish flower head about 2.5 cm (1 inch) in diameter. White clover, a low creeping perennial, is often used in lawn-grass mixtures…

clover: …are red clover (Trifolium pratense), white clover (T. repens), and alsike clover (T. hybridum). Red clover, a biennial, or short-lived perennial, bears an oval purplish flower head about 2.5 cm (1 inch) in diameter. White clover, a low creeping perennial, is often used in lawn-grass mixtures and bears a white…

Yuri Valentinovich Trifonov was a Soviet writer who managed to retain official acceptance of his work despite its anti-Stalinist overtones. Trifonov’s father, a hero of the Russian Revolution of 1917, was executed during a political purge in 1938, and his mother was sent to a prison camp for eight

triforium, in architecture, space in a church above the nave arcade, below the clerestory, and extending over the vaults, or ceilings, of the side aisles. The term is sometimes applied to any second-floor gallery opening onto a higher nave by means of arcades or colonnades, like the galleries in

epic: Bases: …been found in a so-called tripartite ideology or “trifunctional system” of the Indo-Europeans. The concept was based on the discovery of the remarkable philosophy of a prehistoric nation that survived as a system of thought in the historic Indo-European civilizations and even in the subconsciousness of the modern speakers of…

nuclear reactor: TRIGA reactors: The training, research, and isotope-production reactors–General Atomic (TRIGA) system is a popular variety of research reactor. It is another tank-type water-cooled system, but its fuel differs from that employed by the plate-fuel research reactors described above. The fuel element of the TRIGA reactor…

India: Oligarchies and kingdoms: The Trigartas have been associated with the Chamba region of the upper Ravi River, but they also may have inhabited the area of Jalandhara in the plains. The Abhiras lived in scattered settlements in various parts of western and central India as far as the Deccan.…

human nervous system: Trigeminal nerve (CN V or 5): The trigeminal nerve is the largest of the cranial nerves. It has both motor and sensory components, the sensory fibers being general somatic afferent and the motor fibers being special visceral efferent. Most of the cell bodies of sensory…

human nervous system: Trigeminal nerve (CN V or 5): Trigeminal neuralgia, or tic douloureux, is an intense pain originating mainly from areas supplied by sensory fibers of the maxillary and mandibular branches of this nerve.

Pauline Trigère was a French-born American couturiere whose award-winning design work was especially popular in the United States in the 1950s and ’60s. Trigère was the daughter of a tailor. She early learned to sew and helped her mother custom-tailor women’s clothes. After graduating from the

Dale Evans: …horse, Buttermilk, and his horse, Trigger. They were inducted into the National Cowboy Hall of Fame, Oklahoma City, Oklahoma, in 1976. Rogers died in 1998 after nearly 51 years of marriage to Evans.

military technology: The matchlock: …was a simple S-shaped “trigger,” called a serpentine, fastened to the side of a hand cannon’s stock. The serpentine was pivoted in the middle and had a set of adjustable jaws, or dogs, on the upper end that held the smoldering end of a length of match. Pulling up…

Neil Gaiman: The Graveyard Book, The Ocean at the End of the Lane, and other later works: Trigger Warning: Short Fictions and Disturbances (2015) is a collection of brief tales, many of which reference or sprung from the work of other authors and artists. In 2017 Gaiman offered a novel interpretation of Norse myths in Norse Mythology.

triggerfish, any of about 30 species of shallow-water marine fishes of the family Balistidae, found worldwide in tropical seas. Triggerfishes are rather deep-bodied, usually colourful fishes with large scales, small mouths, and high-set eyes. Their common name refers to the triggering mechanism in

Triglav, mountain peak, the highest (9,396 feet [2,864 m]) of Slovenia and of the Julian Alps, situated 40 miles (64 km) northwest of the city of Ljubljana. The north wall of the peak forms an enormous limestone face nearly 2 miles (3 km) wide. From the time of its first ascent in 1778, the summit

sea robin, any of the slim bottom-dwelling fish of the family Triglidae, found in warm and temperate seas of the world. Sea robins are elongated fish with armoured bony heads and two dorsal fins. Their pectoral fins are fan-shaped, with the bottom few rays each forming separate feelers. These

triglyceride, any one of an important group of naturally occurring lipids (fat-soluble components of living cells). Triglycerides are esters in which three molecules of one or more different fatty acids are linked to the alcohol glycerol; they are named according to the fatty acid components; e.g.,

order: It is composed of projecting triglyphs (units each consisting of three vertical bands separated by grooves) that alternate with receding square panels, called metopes, that may be either plain or carved with sculptured reliefs. The Roman forms of the Doric order have smaller proportions and appear lighter and more graceful…

St. Ninian ; feast day September 16) was a bishop generally credited as the first Christian missionary to Scotland, responsible for widespread conversions among the Celts and possibly the Southern Picts. The two primary historical sources about Ninian’s life and work are of dubious reliability.

Abruzzi: Pescara, Sangro, and Trigno) drain to the Adriatic, providing irrigation in their lower courses. The course of these streams is irregular, and, because of massive deforestation on the upper slopes, floods and landslides occur frequently during the spring and fall rains.

children’s literature: Overview: …in the late 1940s, critic Jean de Trigon, in Histoire de la littérature enfantine, de ma Mère l’Oye au Roi Babar (Paris, Librairie Hachette, 1950) said: “The French have created little children’s literature. They have received more than they have given, but they have assimilated, adapted, transformed. The two are…

chemical bonding: Applying VSEPR theory to simple molecules: …and found to be a trigonal bipyramid. The XeF4 (xenon tetrafluoride) molecule is hypervalent with six electron pairs around the central xenon (Xe) atom. These pairs adopt an octahedral arrangement. Four of the pairs are bonding pairs, and two are lone pairs. According to VSEPR theory, the repulsion between the…

chemical bonding: Molecules with no central atom: …the corresponding bonds, adopt a planar triangular arrangement, and the H―C―H and H―C=C angles are predicted to be close to 120°, as is found experimentally. It is less apparent from this analysis, but understandable once it is realized that the superpair is actually two shared pairs (Figure 9), that the…

ammonia: Physical properties of ammonia: …The ammonia molecule has a trigonal pyramidal shape with the three hydrogen atoms and an unshared pair of electrons attached to the nitrogen atom. It is a polar molecule and is highly associated because of strong intermolecular hydrogen bonding. The dielectric constant of ammonia (22 at −34 °C [−29 °F])…

trigonal system, one of the structural categories to which crystalline solids can be assigned. The trigonal system is sometimes considered to be a subdivision of the hexagonal system. Components of crystals in the trigonal system, like those of the hexagonal system, are located by reference to four

renal system: The bladder: …of the bladder neck, or trigone, is demarcated by the two ureteric orifices and the internal opening of the urethra. Muscle fibres loop around the urethral opening to form the internal sphincter, which is under involuntary control. The external sphincter consists of two layers of striated muscles under voluntary control.

fenugreek, (Trigonella foenum-graecum), fragrant herb of the pea family (Fabaceae) and its dried flavourful seeds used as a spice. Native to southern Europe and the Mediterranean region, fenugreek is cultivated in central and southeastern Europe, western Asia, India, and northern Africa. See also

Trigonia, genus of mollusks that first appeared during the Jurassic period, which began about 208 million years ago. The still-extant Trigonia has a triangular shell with distinctive concentric ridges on its surface as well as nodular outgrowths. A different ornamental pattern is present in the

Malpighiales: The Chrysobalanaceae group: In Chrysobalanaceae, Balanopaceae, Trigoniaceae, Dichapetalaceae, and Euphroniaceae, each ovary chamber usually has only two ovules, and the seeds have at most slight endosperm. Within this group, Chrysobalanaceae, Trigoniaceae, Dichapetalaceae, and Euphroniaceae are especially close. All have leaf margins that lack teeth; there are often flat, rarely raised glands…

cricket: Sword-bearing, or winged bush, crickets (subfamily Trigonidiinae) are 4 to 9 mm long and brown and possess a sword-shaped ovipositor. They are characteristically found in bushes near a pond.

bivalve: Annotated classification: Order Trigonioida Shell valves equal, trigonally oval, strongly ribbed; shell with outer aragonitic prismatic layer and inner nacre layers; strong hinge teeth transversely grooved; typically isomyarian, with pedal elevator and protractor muscles as well as retractors; ctenidia filibranch, without mantle fusions; powerful foot; marine; infaunal; living…

craniosynostosis: …a triangularly shaped head (trigonocephaly) and may be accompanied by brain damage.

vulture: Old World vultures: The white-headed vulture (Trigonoceps occipitalis) is about 80 cm (31 inches) long and has a wingspan of about 1.8 metres (6 feet). Black with white secondary wing feathers and belly, it has a high black neck fringe and a massive red beak. This bird has a…

Henry Briggs: His final publication, the Trigonometria Britannica (1633; “Trigonometry in Britain”), covering the application of logarithms to trigonometric functions, appeared posthumously.

trigonometric function, in mathematics, one of six functions (sine [sin], cosine [cos], tangent [tan], cotangent [cot], secant [sec], and cosecant [csc]) that represent ratios of sides of right triangles. These six trigonometric functions in relation to a right triangle are displayed in the figure.

surveying: Triangulation: Trigonometric leveling often is necessary where accurate elevations are not available or when the elevations of inaccessible points must be determined. From two points of known position and elevation, the horizontal position of the unknown point is found by triangulation, and the vertical angles from…

Milky Way Galaxy: The stellar luminosity function: Most commonly, trigonometric parallaxes are employed as the basic sample. Alternative but somewhat less certain methods include the use of spectroscopic parallaxes, which can involve much larger volumes of space. A third method entails the use of mean parallaxes of a star of a given proper motion…

analysis: Trigonometric series solutions: In 1748, in response to d’Alembert’s work, the Swiss mathematician Leonhard Euler wrote a paper, Sur la vibration des cordes (“On the Vibrations of Strings”). In it he repeated d’Alembert’s derivation of the wave equation for a string, but he obtained a…

trigonometry, the branch of mathematics concerned with specific functions of angles and their application to calculations. There are six functions of an angle commonly used in trigonometry. Their names and abbreviations are sine (sin), cosine (cos), tangent (tan), cotangent (cot), secant (sec), and

Augustus De Morgan: In his Trigonometry and Double Algebra (1849) he gave a geometric interpretation of the properties of complex numbers (numbers involving a term with a factor of the square root of minus one) that suggested the idea of quaternions. He made a useful contribution to mathematical symbolism by…

trigonometry table, tabulated values for some or all of the six trigonometric functions for various angular values. Once an essential tool for scientists, engineers, surveyors, and navigators, trigonometry tables became obsolete with the availability of computers. (For reference, the six

pottery: China: The bagua, consisting of eight sets of three lines, broken and unbroken in different combinations, represent natural forces. They are often seen in conjunction with the yin-yang symbol, which represents the female-male principle, and which has been well described by the pottery scholar R.L. Hobson as…

Tigris-Euphrates river system: The Tigris (Sumerian: Idigna; Akkadian: Idiklat; biblical: Hiddekel; Arabic: Dijlah; Turkish: Dicle) is about 1,180 miles (1,900 km) in length.

trigonometry: Spherical trigonometry: …special “angle” known as a trihedral angle is formed. The central angles (also known as dihedral angles) between each pair of line segments OA, OB, and OC are labeled α, β, and γ to correspond to the sides (arcs) of the spherical triangle labeled a, b, and c, respectively. Because…

number game: Flexagons: …the simplest flexagons is the trihexaflexagon, made by cutting a strip of suitable material and marking off 10 equilateral triangles. By folding appropriately several times and then gluing the last triangle onto the reverse side of the first triangle, the resulting model may be flexed so that one of the…

iodoform, a yellow, crystalline solid belonging to the family of organic halogen compounds, used as an antiseptic component of medications for minor skin diseases. First prepared in 1822, iodoform is manufactured by electrolysis of aqueous solutions containing acetone, inorganic iodides, and sodium

therapeutics: Hormones: hormones include thyroxine and triiodothyronine, which regulate tissue metabolism. Natural desiccated thyroid produced from beef and pork and the synthetic derivatives levothyroxine and liothyronine are used in replacement therapy to treat hypothyroidism that results from any cause.

Marcus Terentius Varro: …wrote a political pamphlet entitled Trikaranos (“The Three-Headed”) on the coalition of Pompey, Julius Caesar, and Crassus. He sided with Pompey in Spain (49) but was pardoned (47) and appointed librarian by Caesar, to whom he dedicated the second part of his Antiquitates rerum humanarum et divinarum (“Antiquities of Human…

trikaya, (Sanskrit: “three bodies”), in Mahāyāna Buddhism, the concept of the three bodies, or modes of being, of the Buddha: the dharmakaya (body of essence), the unmanifested mode, and the supreme state of absolute knowledge; the sambhogakaya (body of enjoyment), the heavenly mode; and the

Jayawijaya Mountains: The range’s highest point is Trikora Peak (formerly Wilhelmina Peak; 15,580 feet [4,750 metres]).

Kharílaos Trikoúpis was a statesman who sought with limited success to foster broad-scale national development in Greece during the last quarter of the 19th century. Together with a rival, Theódoros Dhiliyiánnis, he dominated Greek politics during this period. Trikoúpis studied literature and law

Trilateral Commission, organization of private citizens founded in 1973 principally by American banker David Rockefeller to confront challenges posed by the growing interdependence of the United States and its principal allies (Canada, Japan, and the countries of western Europe) and to encourage

Gibraltar: History: …2004 the creation of the Trilateral Forum of Dialogue, bringing together representatives of the governments of Britain, Spain, and Gibraltar, helped to ease tensions. On July 21, 2009, a trilateral meeting in Gibraltar marked the first time since 1704 that a Spanish minister visited the territory. In August 2013 a…

trilateration, method of surveying in which the lengths of the sides of a triangle are measured, usually by electronic means, and, from this information, angles are computed. By constructing a series of triangles adjacent to one another, a surveyor can obtain other distances and angles that would

Trilby, novel by George du Maurier, published in 1894. The novel tells the story of Trilby O’Ferrall, an artist’s model in Paris, who falls under the spell of the compelling Svengali, a musician who trains her voice through hypnosis and turns her into a singing star. The pair travel throughout

César Vallejo: …the more complex poems of Trilce (1922; Eng. trans. Trilce) were conceived during his imprisonment. In his major work Trilce, Vallejo signaled his complete break with tradition by incorporating neologisms, colloquialisms, typographic innovations, and startling imagery, with which he sought to express the disparity that he felt existed between human…

lead processing: Oxides: Red lead, or lead tetroxide (Pb3O4), is another lead oxide whose two most important uses are in paints and as an addition to litharge in storage batteries. It also has significant application in glasses, glazes, and vitreous enamels. Red lead is produced by heating litharge…

Ordovician Period: Earliest land plants: Trilete spores, which divide via meiosis to form a tetrad of cells that disperse separately, first appeared in the late Late Ordovician and form a rare, geographically isolated component in cryptospore assemblages. Although spores are known from older rocks, cryptospore and trilete spores are thought…

Stonehenge: Second stage: 2640–2480 bce: …horseshoe-shaped setting of five tall trilithons (paired uprights with a lintel)—the central and largest of which is known as the giant trilithon—surrounded by 30 uprights linked by curved lintels to form a circle. The stones appear to have been laid out systematically in units and subunits of the long foot;…

trill, in phonetics, a vibration or series of flaps (see flap) of the tongue, lips, or uvula against some other part of the mouth. The Spanish rr in perro (“dog”) is a tongue trill, and the French r is sometimes pronounced as an uvular

Lionel Trilling was an American literary critic and teacher whose criticism was informed by psychological, sociological, and philosophical methods and insights. Educated at Columbia University (M.A., 1926; Ph.D., 1938), Trilling taught briefly at the University of Wisconsin and at Hunter College in

trillium, (genus Trillium), genus of about 25 species of spring-flowering perennial herbs of the family Melanthiaceae, native to North America and Asia. Many species of Trillium are cultivated in wildflower gardens. Trillium plants have oval bracts that resemble and function as leaves and arise

trillium, (genus Trillium), genus of about 25 species of spring-flowering perennial herbs of the family Melanthiaceae, native to North America and Asia. Many species of Trillium are cultivated in wildflower gardens. Trillium plants have oval bracts that resemble and function as leaves and arise

The Devil’s Trill, sonata for violin and basso continuo by Italian composer Giuseppe Tartini, dating from about 1713 or, more likely, according to scholars of Tartini’s style, after 1740. About a dozen years younger than his compatriot Antonio Vivaldi, Tartini was a gifted violinist who wrote

trilobite, any member of a group of extinct fossil arthropods easily recognized by their distinctive three-lobed, three-segmented form. Trilobites, exclusively marine animals, first appeared at 521 million years ago near the beginning of the Cambrian Period (538.8 million to 485.4 million years

trilobite, any member of a group of extinct fossil arthropods easily recognized by their distinctive three-lobed, three-segmented form. Trilobites, exclusively marine animals, first appeared at 521 million years ago near the beginning of the Cambrian Period (538.8 million to 485.4 million years

John Landen: … in 1760 and introduced the trilogarithm. His publications include Mathematical Lucubrations(1755), and A Discourse Concerning the Residual Analysis(1758) in which he tried to rid calculus of the difficult concept of infinitesimals by basing it on the accepted principles of algebra and geometry.

Johann Wolfgang von Goethe: Last years (1817–32) of Johann Wolfgang von Goethe: …“Trilogie der Leidenschaft” (1827; “Trilogy of Passion”).

trilogy, a series of three dramas or literary or musical compositions that, although each is in one sense complete, have a close mutual relation and form one theme or develop aspects of one basic concept. The term originally referred specifically to a group of three tragedies written by one author

The Financier: …an epic series called the Trilogy of Desire, based on the life of Charles T. Yerkes, an American transportation magnate. The other two volumes are The Titan (1914) and The Stoic, which was completed by Dreiser’s wife after his death and published posthumously in 1947.

Johann Wolfgang von Goethe: Last years (1817–32) of Johann Wolfgang von Goethe: …“Trilogie der Leidenschaft” (1827; “Trilogy of Passion”).

airplane: Elevator, aileron, and rudder controls: Trimming the aircraft is a continual process, with adjustments necessary for changes to the flight or power controls that result in changes in speed or attitude.

Trim, market town and seat of County Meath, Ireland, on the River Boyne. It was important from ancient times and was the seat of a bishopric. St. Patrick is said to have founded a monastery there in 432. There are remnants of a 13th-century Augustinian abbey, two gates from the town walls, and

Trim: …walls, and extensive remains of Trim Castle, which was founded in 1173 and was incorporated in the 13th century into the largest Anglo-Norman fortress in Ireland. St. Patrick’s Church (1499) with its castellated tower became a Church of Ireland cathedral in 1955. Industries include textiles and some light manufacturing. Pop.…

airplane: Elevator, aileron, and rudder controls: Trim tabs are used by the pilot to relieve the requirement of maintaining continuous pressure on the controls. These are smaller surfaces inset into the rudder, elevator, and ailerons, which can be positioned by mechanical or electrical means and which, when positioned, move the control…