Encyclopedia

Transportation in Virginia Transportation in the Commonwealth of Virginia is by land, sea and air. Virginia's extensive network of highways and railroads were developed and built over a period almost 400 years, beginning almost immediately after the founding of Jamestown in 1607, and often incorporating old established trails of the Native Americans.
Transportation Library, UC Berkeley The Harmer E. Davis Transportation Library —also known as the Institute of Transportation Studies Library (ITSL), the Berkeley Transportation Library, or simply as the Transportation Library— is a library at the University of California, Berkeley, devoted to transportation studies.
Transportation management system Transportation Management Systems, commonly known as TMS, are a category of operations software (often Web-hosted) under the “supply chain execution” grouping that aids logistics management in various modes along with associated activities, including managing shipping units; shipment scheduling through inbound, outbound and intra-company shipments; modelling and benchmarking, rate management, data base maintenance; generating bills of lading; load planning and optimization; carrier or mode selection; posting and tendering; freight bill auditing and payment; loss and damage claims processing; labour planning and building; documentation management (especially when international shipping is involved); and third party logistics management.
Transportation Materiel Command The Transportation Materiel Command (TMC) was a unit of the US Army, originally headquartered in Marietta, Pennsylvania. In March 1955, it merged with the Transportation Corps Army Aviation Field Service Office (TCAAFSO) to form the Transportation Supply and Maintenance Command (TSMC) headquartered in St.
Transportation of California California's transportation system is dynamic and usually functional, however, in a state with over 30 million people, rapid population expansion, and often difficult terrain and weather, that system is under pressure to stay ahead of population growth and transportation needs.
Transportation of Los Angeles Los Angeles, California, is the center of an intercity hub, transporting passengers and shipping intermodally between sea, land, and air ports. It has an even busier intracity commuter system made up of freeways, roads, buses, light rail and subway.
Transportation Recall Enhancement, Accountability and Documentation Act The Transportation Recall Enhancement, Accountability and Documentation (or TREAD) Act is a United States federal law enacted in the fall of 2000. This law intends to increase consumer safety through mandates assigned to the National Highway Traffic Safety Administration (NHTSA).
Transportation Research Board The Transportation Research Board (TRB) is a division of the National Research Council, which serves as an independent adviser to the President, the Congress and federal agencies on scientific and technical questions of national importance. The National Research Council is jointly administered by the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
Transportation security officer A Transportation Security Officer (TSO) is a federal employee of the United States Transportation Security Administration (TSA) tasked with performing security screening of persons and property at airport terminals and baggage areas. The primary function of a Transportation Security Officer is to prevent all prohibited/dangerous objects from being transported onto aircraft.
Transportation Safety Board of Canada The Transportation Safety Board (Bureau de la sécurité des transports du Canada) is the Canadian agency responsible for maintaining transportation safety in Canada. The agency investigates accidents and makes safety recommendations in several modes of transport, including aviation, rail, marine, and pipelines.
Transportation theory In mathematics and economics, transportation theory is a name given to the study of optimal transportation and allocation of resources. The problem was formalized by the French mathematician Gaspard Monge in 1781G.
Transporter (Star Trek) In the Star Trek fictional universe, transporters are teleportation machines. The devices convert a person or object into an energy pattern (a process called dematerialization), then "beam" it to a target, where it is reconverted into matter (rematerialization).
Transporter bridge A transporter bridge (also ferry bridge or aerial transfer bridge) is a type of movable bridge that carries a segment of roadway across a river. The gondola is slung from a tall span by wires or a metal frame.
Transporter erector launcher A TEL, or transporter erector launcher, describes a vehicle that carries one or more missiles and is able to elevate it into a firing position and launch it without having to remove the missile(s) from the vehicle. Such vehicles exist for both surface-to-air missiles and surface-to-surface missiles.
Transportpolizei The Transportpolizei was the Transit police of the East German volkspolizei that dealt with modes of transit but primarily with trains and railroads. Called TraPo's, they were organized with a directorate at National level and a District at each East German National Railroad district.
Transports en commun lyonnais The Transports en commun lyonnais (usually referred to as TCL) is literally the Lyon public transport system. It is the second largest public transport system in France (after Paris), and covers the 62 communes that make up the Urban community of Lyon, spread over 606 km².
Transports Publics du Chablais In the interests of the communities in the Chablais region, at the eastern end of Lake Geneva, it was decided in 1999, to bring together passenger transport companies, to co-ordinate and develop services and investment in transport in the area. This new grouping became known asTransports Publics du Chablais SA (TPC).
Transports Québec Transports Québec (or the Ministry of Transportation of Quebec, in French: le Ministère des Transports du Québec) is a Quebec government ministry responsible for transport infrastructure and law in Quebec. The current Minister for Transport is Liberal MNA Michel Després.
Transposase Transposase is an enzyme that binds to single-stranded DNA and can incorporate it into genomic DNA. Class II transposons encode a transposase which allows them to enable transposons to be cut from genomic DNA and be inserted at another location.
Transposition (chess) A transposition in chess is a position on the board that can be reached by the same piece in more than one way. A simple example: White can move its knight from g1 to g5 by following either sequence of moves (in algebraic notation): 1.
Transposition (logic) In the methods of deductive reasoning in classical logic, "transposition is the rule of inference that permits one to infer from the truth of "A implies B" the truth of "Not-B implies not-A", and conversely".Brody, Bobuch A.
Transposition (mathematics) In informal language, a transposition is a function that swaps two elements of a set. More formally, given a finite set X={a_1,a_2,ldots,a_n}, a transposition is a permutation (bijective function of X onto itself) f, such that there exist indices i, j such that f(a_i) = a_j, f(a_j) = a_i and f(a_k) = a_k for all other indices k.
Transposition of the great vessels Transposition of the great vessels (TGV) is a group of congenital heart defects (CHDs) involving an abnormal spatial arrangement of any of the primary vessels: superior and/or inferior vena cavae (SVC, IVC), pulmonary artery, pulmonary veins, and aorta. CHDs involving only the primary arteries (pulmonary artery and aorta) belong to a sub-group called transposition of the great arteries (TGA).
Transpositional pun A transpositional pun is a complicated pun format with two aspects. It involves transposing the words in a well-known phrase or saying to get a daffynition-like clever redefinition of a well-known word unrelated to the original phrase.
Transposon Transposons are sequences of DNA that can move around to different positions within the genome of a single cell, a process called transposition. In the process, they can cause mutations and change the amount of DNA in the genome.
Transpyloric plane An upper transverse line, the transpyloric is located halfway between the jugular notch and the upper border of the symphysis pubis; this indicates the margin of the transpyloric plane, which in most cases cuts through the pylorus, the tips of the ninth costal cartilages and the lower border of the first lumbar vertebra.
TransPAC2 The TransPAC2 Network is a National Science Foundation-funded high-speed international circuit connecting research and education networks in the Asia-Pacific region to those in the US. It is the 5-year continuation of the TransPAC project.
TransPennine Express TransPennine Express (TPE) is a train operating company in the United Kingdom. It operates regular regional services in the north of England, including services linking the west and east coasts of England across the Pennines.
TransPennine North West TransPennine North West is one of the three rail services provided by First TransPennine Express, running in Northern England. It runs from Manchester Airport to Windermere, Kendal and Barrow-in-Furness, via Lancaster, Preston, Bolton and Manchester Piccadilly.
Transrapid A work in progress translation of the Transrapid article from German to English is currently underway. If you are confident enough in your fluency of German and English, please feel free to assist with this translation.
Transrealism Transrealism is a literary mode that mixes the techniques of incorporating fantastic elements used in science fiction with the techniques of describing immediate perceptions from naturalistic realism. While combining the strengths of the two approaches, it is largely a reaction to their perceived weaknesses.
Transrectal ultrasonography Transrectal ultrasound uses inaudible sound waves produced by a probe inserted into the rectum to create an image of organs in the pelvis. The most common indication for transrectal ultrasound is for the evaluation of the prostate gland in men with elevated prostate specific antigen or prostatic nodules on digital rectal exam.
Transreflective liquid crystal display A transreflective liquid crystal display is a liquid crystal display (LCD) that reflects most of the sunlight the monitor is exposed to, and automatically increases or decreases the light emanating from the screen depending on how much light shines on it. Therefore, it reduces the need for manual light adjustment of the screen.
Transrockies The TransRockies is an annual 7-day, 600 km mountain bicycle race from Fernie, British Columbia to the Panorama Ski Resort, British Columbia. Described as the "toughest mountain bike race on earth", the TransRockies has a reputation for tough climbs, long days, relentless mud and highly changeable weather.
Transsexualism Transsexualism is a condition in which a transsexual person self-identifies as a member of the gender opposite to the one assigned to them at birth. Transsexualism is considered a taboo subject in many parts of the world.
Transsexuality in Iran Before the Islamic Revolution in 1979, the issue of transsexuality in Iran had never been officially addressed by the government. Beginning in the mid-1980s, however, transgendered individuals have been officially recognized by the government and allowed to undergo sex reassignment surgery.
Transsylvania Phoenix Transsylvania Phoenix or, more commonly, just Phoenix, is one of the most prominent Romanian rock bands of the latest decades, and also the first one to take musical inspiration from ancient Romanian folk themes.
Transtheism Transtheism is the belief in one or more deities in the form of that God/god(s) transcends the universe and are yet immanent. Western and Eastern variants of Transtheism exist, with the emphasis on the individual relative to God being greater in the Western.
Transtheoretical model of change The transtheoretical model of change explains or predicts a person's success or failure in achieving a a proposed change in habits. It attempts to answer why the change "stuck" or alternatively why the change was not made.
Transtherapy Transtherapy is a reform movement in psychotherapy and in the mental helping professions started in the early part of this century. It is an association of practitioners who are critical of the trends of commercialism, medicalization, bureaucratization and idolization in psychotherapy.
Transtibial prosthesis Transtibial amputees have the greatest hope of regaining normal mobility. The knee is the part of the leg involving the most complex biomechanics; as this is intact for all transtibial amputees, the process of mimicking native leg movement becomes much easier for this population.
Transubstantiation Transubstantiation (in Latin, transsubstantiatio) is the change of the substance of bread and wine into that of the body and blood of Christ that, according to the teaching of the Roman Catholic Church, occurs in the Eucharist and that is called in Greek (see Metousiosis).
Transurethral needle ablation of the prostate Transurethral needle ablation (TUNA) is a recently approved technique which can be done with a local anesthetic on an outpatient basis, and uses radio frequency energy delivered through needles to kill excess prostate tissue. A catheter that deploys the needles toward the obstructing prostate tissue is inserted into the urethra before the procedure begins.
TransUnion TransUnion (full name Trans Union LLC) is a consumer credit reporting agency, considered one of the 'big three' agencies in the United States. Like their main competitors, Experian and Equifax, they now market their credit reports directly to consumers, in addition to their core business of providing the reports to potential creditors.
TransUnion Canada TransUnion Canada is one of three credit reporting agencies in Canada. Like their main competitors Equifax Canada, they now market their credit reports directly to consumers, in addition to their core business of providing the reports to potential creditors.
Transvaal Horse Artillery The Transvaal Horse Artillery (usually abbreviated to "THA") is an artillery regiment of the South African Army. As a reserve unit, it has a status roughly equivalent to that of a British Territorial Army or United States Army National Guard unit.
Transvaal Park Transvaal Park was a popular water park in Yasenevo, a suburb south of Moscow, Russia. With several large, heated pools, including a wave pool and twisting "river" for tubing, it had become one of the most popular attractions in the Moscow area and a symbol of the country's bloom of private enterprise.
Transvaal Scottish Regiment The Transvaal Scottish Regiment is an infantry regiment of the South African Army. As a reserve unit, it has a status roughly equivalent to that of a British Territorial Army or United States Army National Guard unit.
Transvaalse Staatsartillerie The Transvaalse Staatsartillerie (Afrikaans for Transvaal State Artillery) is an artillery regiment of the South African Army. As a reserve unit, it has a status roughly equivalent to that of a British Territorial Army or United States Army National Guard unit.
Transvection (genetics) Transvection is an epigenetic phenomenon that results from an interaction between an allele on one chromosome and the corresponding allele on the homologous chromosome. Transvection can lead to either gene activation or repression.
Transversality Transversality in mathematics is a notion that describes how spaces can intersect; transversality can be seen as the "opposite" of tangency, and plays a role in general position. It formalizes the idea of a generic intersection in differential topology.
Transverse fissure of liver The porta hepatis or transverse fissure is a short but deep fissure, about 5 cm. long, extending transversely across the under surface of the left portion of the right lobe, nearer its posterior surface than its anterior border.
Transverse isotropy A transversely isotropic material is symmetric about an axis that is normal to a plane of isotropy. This transverse plane has infinite planes of symmetry and thus, within this plane, the material properties are same in all directions.
Transverse processes The transverse processes of a vertebra, two in number, project one at either side from the point where the lamina joins the pedicle, between the superior and inferior articular processes. They serve for the attachment of muscles and ligaments.
Transverse redundancy check In telecommunications, a transverse redundancy check (TRC) or vertical redundancy check is a redundancy check for synchronized parallel bit streams, (a) that is based on the formation of a block check following preset rules, (b) in which the check-formation rule applied to blocks is also applied to characters, and (c) in which the check is made on parallel bit patterns.
Transversus abdominis muscle The transversus abdominis muscle, also known as the transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior and lateral abdominal wall which is just deep to (layered below) the internal oblique muscle. It is a major muscle of the functional core of the human body.
Transverter A transverter is a radio frequency device that consists of an upconverter and a downconverter in one unit. Transverters are used in conjunction with transceivers to change the range of frequencies over which the transceiver can communicate.
Transvestism Transvestism is literally the practice of cross-dressing, wearing the clothing of the opposite sex, and transvestite literally refers to a person who cross-dresses. However, the word has often had additional connotations.
Transvestophilia Transvestophilia, or paraphilic transvestism, is a paraphilia in which a person with an apparently normal somatic sexual differentiation has the conviction that he or she is actually a member of the opposite sex. This conviction which is accompanied by a profound sense of loathing for individuals's own primary and Secondary sex characteristics, is absolute, overwhelming and unalterable.
Transvision Vamp Transvision Vamp were a popular UK alternative rock group. Formed in 1986 by Dave Parsons (formerly of the punk band The Partisans), they enjoyed a brief period of success in the late 1980s, fusing elements of punk, art rock and the "big band" sound of Phil Spector.
Transwa Australind The Transwa Australind is a passenger train operated by Transwa that runs between Perth, Western Australia, and the south-west city of Bunbury on the South Western Railway (Western Australia). The Australind service consists of three powered railcars ADP101, ADP102 and ADP103, with two non-driving trailers ADQ121 and ADQ122.
Transwa Avonlink The AvonLink is a standard gauge passenger train operated by Transwa that operates between Perth, Western Australia and the Avon Valley. It provides two services every weekday to the regional town of Northam, and since 2004, has provided three extended services a week to the town of Merredin.
Transwa Prospector The Transwa Prospector is a standard gauge passenger train operated by Transwa that runs between Perth, Western Australia, and the Goldfields town of Kalgoorlie. It replaced the narrow gauge overnight passenger train called the The Westland that ran on the older Eastern Railway (Western Australia) route.
Transwestern Commercial Services Transwestern Commercial Services is one of the largest privately held, full-service real estate firms in the United States. Services offered include agency leasing, property and facility management, investment services, tenant representation, development, corporate advisory, healthcare advisory, and research.
Transwestern Pipeline Transwestern Pipeline is a natural gas pipeline which brings gas from the San Juan Basin and Permian Basin to either California and Arizona or to the Oklahoma panhandle. It is owned by CrossCountry Energy Corporation.
Transwoman A transwoman (also spelled trans-woman) is a transsexual or transgender person who was physically assigned as male at birth, but believes that this is not an accurate or complete description of herself and identifies as a woman.
Transworld depravity Transworld depravity is a concept explained by Alvin Plantinga as the claim that given any possible world in which a free person (P) exists, P will on certain occasions act morally wrong with respect to an action. He claims that this may not only be a property possesed by some, but rather a universal property of individuals.
Transylvania (computer game) Transylvania was the name of a trilogy of computer games released for several home computers of the 1980s. The games were graphic adventure games created by Antonio Antiochia and produced by the now defunct Penguin Software.
Transylvania (TV series) Transylvania was an aborted spin-off television series of the film Van Helsing set in the region of the same name. NBC was going to use the film's village sets setting it in the same 19th century time period as the film, but instead focus on the adventures of a Texas cowboy who becomes sheriff in a Transylvanian village, where he must keep the peace between two warring families with some "monsterous genes".
Transylvania Community Hospital Transylvania Community Hospital (TCH) is a Joint Commission on Accreditation of Healthcare Organizations accredited 94-bed non-profit hospital. It was formed in 1933 and is located between downtown Brevard and the entrance to Pisgah National Forest in Transylvania County, North Carolina.
Transylvania in fiction Largely as a result of the success of Dracula, Transylvania has become a popular setting for horror fiction (particularly that involving vampires). This is odd since according to popular opinion, Dracula was based on Vlad Tepes, who lived in neighboring Wallachia.
Transylvanian Memorandum The Transylvanian Memorandum was a petition sent in 1892 by the leaders of the Romanians of Transylvania to the Austro-Hungarian Emperor-King Franz Joseph, asking for equal ethnic rights with the Hungarians, and demanding an end to persecutions and Magyarization attempts.
Transylvanian Mountains Transylvanian Mountains is the general name of the mountain system that surrounds the Transylvanian highland or plateau on all four sides, and forms the southeastern and southern continuation of the Carpathian Mountains. At the mouths of the ViĹźeu River and the Golden BistriĹŁa River, where the Eastern or Wooded Carpathians end, the range of mountains divides and sends ramifications in two directions, to the south and to the west.
Transylvanian Plateau Transylvanian Plateau is a plateau in central Romania almost entirely surrounded by the Eastern, Southern and Romanian Western branches of the Carpathian Mountains. The Transylvanian Plateau, the Carpathian Mountains, and the lowlands in Western Romania are characterized by continental climate.
Transylvanian School The Transylvanian School (Şcoala Ardeleană in Romanian) was a cultural movement which was founded after part of the Romanian Orthodox Church in Habsburg-ruled Transylvania accepted the leadership of the Pope and became the Greek-Catholic Church (ca.1700).
Transyt Transyt is a piece of software developed in the UK by the Transport Research Laboratory. It is used to assess and optimise the performance of networks of road junctions by assigning costs to vehicle stops and delays.
TranSouth Athletic Conference The TranSouth Athletic Conference is a college athletic conference for smaller colleges and universities located in the Southern United States. It is affiliated with the National Association of Intercollegiate Athletics (NAIA) and competes in that organization's Region XI.
Trantasia Trantasia is a feature film documentary chronicling 6 contestants in the first ever 'World's Most Beautiful Transsexual Pageant'. The pageant was created by Las Vegas producer Norbert Aleman and hosted by former Las Vegas showgirl Jahna Steele, who created quite a stir in the 90's when she was outed as having been born a man.
TranWare TranWare(TM) is a proprietary software system used for the management of ground transportation fleets such as Taxicab, Paratransit (non-emergency medical), Executive Sedan, Airport Shuttle and localized Courier. It includes modules for Order Entry, Scheduling, Dispatching, Driver Cashiering, Account Billing, Vehicle Maintenance, Automated Wireless Dispatching and Automatic Vehicle Location via GPS.
Tranz Scenic Tranz Scenic is the long-distance passenger rail division of Toll Rail, formed from the New Zealand Railways Corporation InterCity Rail services. Tranz Scenic was renamed along with the other operating divisions of Tranz Rail in 1995.
TranzAlpine The TranzAlpine is a passenger train service operated by Tranz Scenic, operating in the South Island of New Zealand. This trip is often regarded to be one of the ten great train journeys in the world for the amazing scenery through which it passes, (see Famous trains).
TranzCoastal The TranzCoastal is a long-distance passenger train between Picton and Christchurch in the South Island of New Zealand, operated by Tranz Scenic. It was known as the Coastal Pacific at the time of its introduction.
Trap (game) Trap is a late 1980s text-based computer game for BASIC designed by People's Computer Company similar to Number, in which one must guess and "trap" a number from one to 100, which the computer is "thinking of." The game appeared on page 5 of the book What to Do After You Hit Return or P.
Trap Door Forage Wagon A Trap Door Forage Wagon is a type of farming wagon that can unload without the operator having to stop. It earned top honors in the American Farm Bureau Federation's 14th annual Farmer Idea Exchange in the annual convention.
Trap Door Spiders The Trap Door Spiders is the name of a literary male-only eating, drinking, and arguing society in New York City, with a membership historically composed of notable science fiction personalities. The name is a reference to the exclusive habits of the trapdoor spider, which when it enters its burrow pulls the hatch shut behind it.
Trap primer A trap primer is a plumbing device or valve that adds water to traps. The water seals in traps are needed to prevent sewer gases from entering buildings, but because this water is exposed to the air, it is subject to evaporation over time.
Trap rock Trap rock is a form of plutonic igneous rock that tends to form polygonal vertical fractures, most typically hexagonal, but also four to eight sided. The fracture pattern forms when magma of suitable chemical composition (typically basaltic) intrudes as a sill or extrudes as a thick lava flow, and slowly cools.
Trap room A trap room is a large open space under the stage of many large theaters. The trap room allows the stage floor to be leveled, extra electrical equipment to be attached, and most importantly, the placement of trap doors onto the stage (hence the name).
Trap run In American football, a trap play, or trap run, is a run consisting of a defender on the line of scrimmage (either a defensive tackle or defensive end) getting trap blocked by an offensive lineman or back from the opposite (other side of the center) side of the ball. One of the defensive linemen will remained un-blocked on a trap and either a backside guard/tackle/h-back will pull down the line of scrimmage and kick him out so that the ball carrier can run inside of that trap block.
Trap shooting Trap shooting is one of the three major forms of competitive shotgun shooting at clay targets (the others are Skeet shooting and sporting clays). There are many versions including Olympic Trap, Double Trap (which is also an Olympic event), Nordic Trap, and several national versions such as American Trap.
Trap street A trap street is a fictitious street included on a map, often outside the area the map covers, for the purpose of "trapping" potential copyright violators of the map, who will be unable to justify the inclusion of the "trap street" on their map.
Trap-Neuter-Return Trap-Neuter-Return (TNR), also known as Trap-Test-Vaccinate-Alter-Release (TTVAR), is a method being promoted as a humane alternative to euthanasia for managing and reducing feral cat populations. TNR relies on sterilization of the cats so that they don't breed.
Trapdoor function A trapdoor function is a function that is easy to compute in one direction, yet believed to be difficult to compute in the opposite direction (finding its inverse) without special information, called the "trapdoor". Trapdoor functions are widely used in cryptography.
Trapdoor spider Trapdoor spiders (superfamily Ctenizoidea, family Ctenizidae) are medium-sized mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation and silk. The trapdoor is difficult to see when it is closed because the plant and soil materials effectively camouflage it.
Trapez Trapez is a label of the Traum Schallplatten group consisting of four record labels Traum,Trapez, Trapez ltd and MBF. It is run by Jacqueline Klein and Riley Reinhold/ Triple R and it is part of the influential Cologne minimal techno scene.
Trapez ltd Trapez ltd is a label of the Traum Schallplatten group consisting of four labels Traum,Trapez, Trapez ltd and MBF. It is run by Jacqueline Klein and Riley Reinhold/ Triple R and it is part of the influential Cologne minimal techno scene.
Trapeze (band) Trapeze were an English rock band formed in March 1969, by vocalist John Jones and guitarist and keyboardist Terry Rowley (who named the band), with singer and guitarist Mel Galley, bassist Glenn Hughes, and drummer Dave Holland. The band had a fairly fluid line up, finally dissolving in 1994, and although they never found commercial success themselves, several members went on to join better known bands including Black Sabbath, Deep Purple, Whitesnake, Judas Priest and Uriah Heep.
Trapeze (sailing) In Sailing, the trapeze refers to a wire that comes from a point high on the mast, usually where the shrouds are fixed, to a hook on the crew member's harness at approximately waist level. The position when extended on the trapeze is outside the hull, braced against it (or an extension of it outwards) with the soles of the feet, facing the masthead, and clipped on by a hook on the trapeze harness.
Trapezium (astronomy) The Trapezium, or Orion Trapezium Cluster is a tight open cluster of stars that lies within the heart of the Orion Nebula, in the constellation of Orion. It was discovered by Galileo Galilei in 1617, who sketched three of the stars (A, C, D) but somehow missed the surrounding nebulosity.
Trapezoid A trapezoid (in North America) or trapezium (in Britain and elsewhere) is a quadrilateral two of whose sides are parallel to each other. Some authors define it as a quadrilateral having exactly one pair of parallel sides, so as to exclude parallelograms.

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