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Dance is a performing artform consisting of purposefully selected sequences of human movement. This movement has aesthetic and symbolic value, and is acknowledged as dance by performers and observers within a particular culture. Dance can be categorized and described by its choreography, by its repertoire of movements, or by its historical period or place of origin.


Data analysis

Data analysis is a process of inspecting, cleansing, transforming, and modeling data with the goal of discovering useful information, informing conclusions, and supporting decision-making. Data analysis has multiple facets and approaches, encompassing diverse techniques under a variety of names, and is used in different business, science, and social science domains. In today’s business world, data analysis plays a role in making decisions more scientific and helping businesses operate more effectively.

Data mining is a particular data analysis technique that focuses on statistical modeling and knowledge discovery for predictive rather than purely descriptive purposes, while business intelligence covers data analysis that relies heavily on aggregation, focusing mainly on business information. In statistical applications, data analysis can be divided into descriptive statistics, exploratory data analysis (EDA), and confirmatory data analysis (CDA). EDA focuses on discovering new features in the data while CDA focuses on confirming or falsifying existing hypotheses. Predictive analytics focuses on the application of statistical models for predictive forecasting or classification, while text analytics applies statistical, linguistic, and structural techniques to extract and classify information from textual sources, a species of unstructured data. All of the above are varieties of data analysis.

Data integration is a precursor to data analysis, and data analysis is closely linked to data visualization and data dissemination.


Data mining

Data mining is a process of extracting and discovering patterns in large data sets involving methods at the intersection of machine learning, statistics, and database systems. Data mining is an interdisciplinary subfield of computer science and statistics with an overall goal to extract information (with intelligent methods) from a data set and transform the information into a comprehensible structure for further use. Data mining is the analysis step of the “knowledge discovery in databases” process, or KDD. Aside from the raw analysis step, it also involves database and data management aspects, data pre-processing, model and inference considerations, interestingness metrics, complexity considerations, post-processing of discovered structures, visualization, and online updating.

The term “data mining” is a misnomer, because the goal is the extraction of patterns and knowledge from large amounts of data, not the extraction (mining) of data itself. It also is a buzzword and is frequently applied to any form of large-scale data or information processing (collection, extraction, warehousing, analysis, and statistics) as well as any application of computer decision support system, including artificial intelligence (e.g., machine learning) and business intelligence. The book Data mining: Practical machine learning tools and techniques with Java (which covers mostly machine learning material) was originally to be named just Practical machine learning, and the term data mining was only added for marketing reasons. Often the more general terms (large scale) data analysis and analytics—or, when referring to actual methods, artificial intelligence and machine learning—are more appropriate.


Data processing

Data processing is, generally, “the collection and manipulation of items of data to produce meaningful information.” In this sense it can be considered a subset of information processing, “the change (processing) of information in any manner detectable by an observer.”

The term Data Processing (DP) has also been used to refer to a department within an organization responsible for the operation of data processing applications.



Daydreaming is the stream of consciousness that detaches from current external tasks when attention drifts to a more personal and internal direction. This phenomenon is common in people’s daily life shown by a large-scale study in which participants spend 47% of their waking time on average on daydreaming. There are various names of this phenomenon including mind wandering, fantasy, spontaneous thoughts, etc. Daydreaming is the term used by Jerome L. Singer whose research programs laid the foundation for nearly all the subsequent research in this area today. The list of terminologies assigned by researchers today puts challenges on identifying the common features of the phenomenon, in this case daydreaming, and on building collective work among researchers.



In psychology, decision-making (also spelled decision making and decisionmaking) is regarded as the cognitive process resulting in the selection of a belief or a course of action among several possible alternative options, it could be either rational or irrational. Decision-making process is a reasoning process based on assumptions of values, preferences and beliefs of the decision-maker. Every decision-making process produces a final choice, which may or may not prompt action.


Decision theory

Decision theory (or the theory of choice not to be confused with choice theory) is the study of an agent’s choices. Decision theory can be broken into two branches: normative decision theory, which analyzes the outcomes of decisions or determines the optimal decisions given constraints and assumptions, and descriptive decision theory, which analyzes how agents actually make the decisions they do.

Decision theory is closely related to the field of game theory and is an interdisciplinary topic, studied by economists, statisticians, data scientists, psychologists, biologists, political and other social scientists, philosophers and computer scientists.

Empirical applications of this rich theory are usually done with the help of statistical and econometric methods.


Deductive reasoning

Deductive reasoning, also deductive logic, is the process of reasoning from one or more statements (premises) to reach a logical conclusion.

Deductive reasoning goes in the same direction as that of the conditionals, and links premises with conclusions. If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true.

Deductive reasoning (“top-down logic”) contrasts with inductive reasoning (“bottom-up logic”): in deductive reasoning, a conclusion is reached reductively by applying general rules which hold over the entirety of a closed domain of discourse, narrowing the range under consideration until only the conclusion(s) remains. In deductive reasoning there is no epistemic uncertainty. In inductive reasoning, the conclusion is reached by generalizing or extrapolating from specific cases to general rules resulting in a conclusion that has epistemic uncertainty.

The inductive reasoning is not the same as induction used in mathematical proofs – mathematical induction is actually a form of deductive reasoning.

Deductive reasoning differs from abductive reasoning by the direction of the reasoning relative to the conditionals. The idea of “deduction” popularized in Sherlock Holmes stories is technically abduction, rather than deductive reasoning. Deductive reasoning goes in the same direction as that of the conditionals, whereas abductive reasoning goes in the direction contrary to that of the conditionals.


Defence mechanism

In psychoanalytic theory, a defence mechanism is an unconscious psychological mechanism that reduces anxiety arising from unacceptable or potentially harmful stimuli.

Defence mechanisms may result in healthy or unhealthy consequences depending on the circumstances and frequency with which the mechanism is used. Defence mechanisms (German: Abwehrmechanismen) are psychological strategies brought into play by the unconscious mind to manipulate, deny, or distort reality in order to defend against feelings of anxiety and unacceptable impulses and to maintain one’s self-schema or other schemas. These processes that manipulate, deny, or distort reality may include the following: repression, or the burying of a painful feeling or thought from one’s awareness even though it may resurface in a symbolic form; identification, incorporating an object or thought into oneself; and rationalization, the justification of one’s behaviour and motivations by substituting “good” acceptable reasons for the actual motivations. In psychoanalytic theory, repression is considered as the basis for other defence mechanisms.


Dental technician

A dental technologist (dental laboratory technician) is a member of the dental team who, upon prescription from a dental clinician, constructs custom-made restorative and dental appliances.

There are four major disciplines within dental technology. These are fixed prosthesis including crowns, bridges and implants; removable prosthesis, including dentures and removable partial dentures; maxillofacial prosthesis, including ocular prosthesis and craniofacial prosthesis; and orthodontics and auxiliaries, including orthodontic appliances and mouthguards.

The dentist communicates with the dental technologist with prescriptions, drawings, and measurements taken from the patient. The most important aspect of this is a dental impression into which the technologist flows a gypsum dental stone to create a replica of the patient’s anatomy known as a dental cast. A technologist can then use this cast for the construction of custom appliances.



A dentist, also known as a dental surgeon, is a medical professional who specializes in dentistry, the diagnosis, prevention, and treatment of diseases and conditions of the oral cavity. The dentist’s supporting team aids in providing oral health services. The dental team includes dental assistants, dental hygienists, dental technicians, and sometimes dental therapists.



Dentistry, also known as dental medicine and oral medicine, is a branch of medicine that consists of the study, diagnosis, prevention, and treatment of diseases, disorders, and conditions of the oral cavity, commonly in the dentition but also the oral mucosa, and of adjacent and related structures and tissues, particularly in the maxillofacial (jaw and facial) area. Although primarily associated with teeth among the general public, the field of dentistry or dental medicine is not limited to teeth but includes other aspects of the craniofacial complex including the temporomandibular joint and other supporting, muscular, lymphatic, nervous, vascular, and anatomical structures.


Major depressive disorder

Major depressive disorder (MDD), also known simply as depression, is a mental disorder characterized by at least two weeks of pervasive low mood. Low self-esteem, loss of interest in normally enjoyable activities, low energy, and pain without a clear cause are common symptoms. Those affected may also occasionally have delusions or hallucinations. Some people have periods of depression separated by years, while others nearly always have symptoms present. Major depression is more severe and lasts longer than sadness, which is a normal part of life.



A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process, or the result of that plan or specification in the form of a prototype, product or process. The verb to design expresses the process of developing a design. In some cases, the direct construction of an object without an explicit prior plan (such as in craftwork, some engineering, coding, and graphic design) may also be considered to be a design activity. The design usually has to satisfy certain goals and constraints, may take into account aesthetic, functional, economic, or socio-political considerations, and is expected to interact with a certain environment. Major examples of designs include architectural blueprints, engineering drawings, business processes, circuit diagrams, and sewing patterns.

The person who produces a design is called a designer, which is a term generally used for people who work professionally in one of the various design areas—usually specifying which area is being dealt with (such as a fashion designer, product designer, web designer or interior designer), but also others such as architects and engineers. A designer’s sequence of activities is called a design process, possibly using design methods. The process of creating a design can be brief (a quick sketch) or lengthy and complicated, involving considerable research, negotiation, reflection, modeling, interactive adjustment and re-design.



Desire is the emotion of longing or hoping for a person, object, or outcome. The same sense is expressed by words such as “craving”. When a person desires something or someone, their sense of longing is excited by the enjoyment or the thought of the item or person, and they want to take actions to obtain their goal. The motivational aspect of desire has long been noted by philosophers (for example, stating that human desire is the fundamental motivation of all human action) as well as by scientists (see motivational salience).

Marketing and advertising companies have used psychological research on how desire is stimulated to find more effective ways to induce consumers into buying a given product or service. While some advertising attempts to give buyers a sense of lack or wanting, other types of advertising create desire associating the product with desirable attributes, by showing either a celebrity or a model with the product.



Destiny, sometimes referred to as fate (from Latin fatum “decree, prediction, destiny, fate”), is a predetermined course of events. It may be conceived as a predetermined future, whether in general or of an individual.



A detective is an investigator, usually a member of a law enforcement agency. They often collect information to solve crimes by talking to witnesses and informants, collecting physical evidence, or searching records in databases. This leads them to arrest criminals and enable them to be convicted in court. A detective may work for the police or privately.


Developmental biology

Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism.



Dice (singular die or dice) are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating random numbers, commonly as part of tabletop games, including dice games, board games, role-playing games, and games of chance.

A traditional die is a cube with each of its six faces marked with a different number of dots (pips) from one to six. When thrown or rolled, the die comes to rest showing a random integer from one to six on its upper surface, with each value being equally likely. Dice may also have polyhedral or irregular shapes and may have faces marked with numerals or symbols instead of pips. Loaded dice are designed to favor some results over others for cheating or entertainment.


Didactic method

A didactic method (Greek: διδάσκειν didáskein, “to teach”) is a teaching method that follows a consistent scientific approach or educational style to present information to students. The didactic method of instruction is often contrasted with dialectics and the Socratic method; the term can also be used to refer to a specific didactic method, as for instance constructivist didactics.


Diet (nutrition)

In nutrition, diet is the sum of food consumed by a person or other organism. The word diet often implies the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are Omnivores, each culture and each person holds some food preferences or some food taboos. This may be due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthy. Complete nutrition requires ingestion and absorption of vitamins, minerals, essential amino acids from protein and essential fatty acids from fat-containing food, also food energy in the form of carbohydrate, protein, and fat. Dietary habits and choices play a significant role in the quality of life, health and longevity.



Dieting is the practice of eating food in a regulated and supervised fashion to decrease, maintain, or increase body weight, or to prevent and treat diseases, such as diabetes and obesity. A restricted diet is more often pursued by those wanting to lose weight. Continuous dieting is recommended by US guidelines for obese or diabetic individuals to reduce body weight and improve general health. Some people follow a diet to gain weight (usually in the form of muscle). Diets can also be used to maintain a stable body weight and improve health.



A dietitian, medical dietitian, or dietician is an expert in identifying and treating disease-related malnutrition and in conducting medical nutrition therapy, for example designing an enteral tube feeding regimen or mitigating the effects of cancer cachexia. Many dietitians work in hospitals and usually see specific patients where a nutritional assessment and intervention has been requested by a doctor or nurse, for example if a patient has lost their ability to swallow or requires artificial nutrition due to intestinal failure. Dietitians are the only regulated healthcare professionals licensed to assess, diagnose, and treat such problems. In the United Kingdom, dietitian is a ‘protected title’, meaning identifying yourself as a dietitian without appropriate education and registration is prohibited by law.


Differential psychology

Differential psychology studies the ways in which individuals differ in their behavior and the processes that underlie it. This is a discipline that develops classifications (taxonomies) of psychological individual differences. This is distinguished from other aspects of psychology in that although psychology is ostensibly a study of individuals, modern psychologists often study groups, or attempt to discover general psychological processes that apply to all individuals. This particular area of psychology was first named and still retains the name of “differential psychology” by William Stern in his book (1900).

While prominent psychologists, including Stern, have been widely credited for the concept of individual differences, historical records show that it was Charles Darwin (1859) who first spurred the scientific interest in the study of individual differences. His interest was further pursued by his half-cousin Francis Galton in his attempt to quantify individual differences among people.

For example, in evaluating the effectiveness of a new therapy, the mean performance of the therapy in one treatment group might be compared to the mean effectiveness of a placebo (or a well-known therapy) in a second, control group. In this context, differences between individuals in their reaction to the experimental and control manipulations are actually treated as errors rather than as interesting phenomena to study. This approach is applied because psychological research depends upon statistical controls that are only defined upon groups of people.



Dignity is the right of a person to be valued and respected for their own sake, and to be treated ethically. It is of significance in morality, ethics, law and politics as an extension of the Enlightenment-era concepts of inherent, inalienable rights. The term may also be used to describe personal conduct, as in “behaving with dignity”.



Occupations and positions

Arts and design:
Animation director
Artistic director
Creative director
Design director
Film director
Music director
Music video director
Sports director
Television director
Theatre director
Positions in other fields:
Director (business), a senior level management position
Director (colonial), head of chartered company’s colonial administration in a territory
Director (education), head of a university or other educational body
Company director
Cruise director
Executive director
Finance director or chief financial officer
Funeral director
Managing director
Non-executive director
Technical director
Tournament director

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A disability is a societal imposition on people who have impairments, making it more difficult for people to do certain activities or interact with the world around them. Due to cognitive, developmental, intellectual, mental, physical, and/or sensory differences, disabled people are “unnecessarily isolated and excluded from full participation in society.” As a result of impairments, people with disabilities can experience disablement from birth, or may be labeled as disabled during their lifetime. The United Nations Convention on the Rights of Persons with Disabilities defines disability as:

long-term physical, mental, intellectual or sensory impairments which in interaction with various barriers may hinder [a person’s] full and effective participation in society on an equal basis with others.


Discrete emotion theory

Discrete emotion theory is the claim that there is a small number of core emotions. For example, Silvan Tomkins (1962) concluded that there are eight basic emotions: surprise, interest, joy, rage, fear, disgust, shame, and anguish. More recently, Carroll Izard at the University of Delaware factor analytically delineated 12 discrete emotions labeled: Interest, Joy, Surprise, Sadness, Anger, Disgust, Contempt, Self-Hostility, Fear, Shame, Shyness, and Guilt (as measured via his Differential Emotions Scale or DES-IV).

Discrete emotion theory states that these specific core emotions are biologically determined emotional responses whose expression and recognition is fundamentally the same for all individuals regardless of ethnic or cultural differences.


Diseases of affluence

Diseases of affluence, previously called diseases of rich people, is a term sometimes given to selected diseases and other health conditions which are commonly thought to be a result of increasing wealth in a society. Also referred to as the “Western disease” paradigm, these diseases are in contrast to so-called “diseases of poverty”, which largely result from and contribute to human impoverishment. These diseases of affluence have vastly increased in prevalence since the end of World War II.

Examples of diseases of affluence include mostly chronic non-communicable diseases (NCDs) and other physical health conditions for which personal lifestyles and societal conditions associated with economic development are believed to be an important risk factor — such as type 2 diabetes, asthma, coronary heart disease, cerebrovascular disease, peripheral vascular disease, obesity, hypertension, cancer, alcoholism, gout, and some types of allergy. They may also be considered to include depression and other mental health conditions associated with increased social isolation and lower levels of psychological well being observed in many developed countries. Many of these conditions are interrelated, for example obesity is thought to be a partial cause of many other illnesses.

In contrast, the diseases of poverty have tended to be largely infectious diseases, or the result of poor living conditions. These include tuberculosis, malaria, and intestinal diseases. Increasingly, research is finding that diseases thought to be diseases of affluence also appear in large part in the poor. These diseases include obesity and cardiovascular disease and, coupled with infectious diseases, these further increase global health inequalities.

Diseases of affluence started to become more prevalent in developing countries as diseases of poverty decline, longevity increases, and lifestyles change. In 2008, nearly 80% of deaths due to NCDs — including heart disease, strokes, chronic lung diseases, cancers and diabetes — occurred in low- and middle-income countries.



Disgust (Middle French: desgouster, from Latin gustus, “taste”) is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful, or unpleasant. In The Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste (either perceived or imagined), and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research continually has proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder (also known as OCD).



Disinformation is false or misleading information that is spread deliberately to deceive. This is a subset of misinformation.

The English word disinformation is a loan translation of the Russian dezinformatsiya, derived from the title of a KGB black propaganda department. Joseph Stalin coined the term, giving it a French-sounding name to claim it had a Western origin. Russian use began with a “special disinformation office” in 1923. Disinformation was defined in Great Soviet Encyclopedia (1952) as “false information with the intention to deceive public opinion”. Operation INFEKTION was a Soviet disinformation campaign to influence opinion that the U.S. invented AIDS. The U.S. did not actively counter disinformation until 1980, when a fake document reported that the U.S. supported apartheid.

The word disinformation did not appear in English dictionaries until the late-1980s. English use increased in 1986, after revelations that the Reagan Administration engaged in disinformation against Libyan leader Muammar Gaddafi. By 1990, it was pervasive in U.S. politics; and by 2001 referred generally to lying and propaganda.



A district is a type of administrative division that, in some countries, is managed by local government. Across the world, areas known as “districts” vary greatly in size, spanning regions or counties, several municipalities, subdivisions of municipalities, school district, or political district.



Deoxyribonucleic acid (/diːˈɒksɪˌraɪboʊnjuːˌkliːɪk, -ˌkleɪ-/ (About this soundlisten); DNA) is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids. Alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.


DNA computing

DNA computing is an emerging branch of computing which uses DNA, biochemistry, and molecular biology hardware, instead of the traditional electronic computing. Research and development in this area concerns theory, experiments, and applications of DNA computing. Although the field originally started with the demonstration of a computing application by Len Adleman in 1994, it has now been expanded to several other avenues such as the development of storage technologies, nanoscale imaging modalities, synthetic controllers and reaction networks, etc.



A doctorate (from Latin docere, “to teach”) or doctor’s degree (from Latin doctor, “teacher”) or doctoral degree, is an academic degree awarded by universities, derived from the ancient formalism licentia docendi (“licence to teach”). In most countries, it is a research degree that qualifies the holder to teach at university level in the degree’s field, or to work in a specific profession. There are a number of doctoral degrees; the most common is the Doctor of Philosophy (PhD), which is awarded in many different fields, ranging from the humanities to scientific disciplines.



Documentation is any communicable material that is used to describe, explain or instruct regarding some attributes of an object, system or procedure, such as its parts, assembly, installation, maintenance and use. Documentation can be provided on paper, online, or on digital or analog media, such as audio tape or CDs. Examples are user guides, white papers, online help, and quick-reference guides. Paper or hard-copy documentation has become less common.[citation needed] Documentation is often distributed via websites, software products, and other online applications.

Documentation as a set of instructional materials shouldn’t be confused with documentation science, the study of the recording and retrieval of information.



Dominoes is a family of tile-based games played with gaming pieces, commonly known as dominoes. Each domino is a rectangular tile with a line dividing its face into two square ends. Each end is marked with a number of spots (also called pips or dots) or is blank. The backs of the tiles in a set are indistinguishable, either blank or having some common design. The gaming pieces make up a domino set, sometimes called a deck or pack. The traditional European domino set consists of 28 tiles, also known as pieces, bones, rocks, stones, men, cards or just dominoes, featuring all combinations of spot counts between zero and six. A domino set is a generic gaming device, similar to playing cards or dice, in that a variety of games can be played with a set.


Doorman (profession)

A doorman (also porter in British English) is a person hired to provide courtesy and security services at a residential building or hotel. They are particularly common in urban luxury highrises. At a residential building, a doorman is responsible for opening doors and screening visitors and deliveries. They will often provide other courtesy services such as signing for packages, carrying luggage between the elevator and the street, or hailing taxis for residents and guests.



Draughts (/drɑːfts, dræfts/; British English) or checkers (American English) is a group of strategy board games for two players which involve diagonal moves of uniform game pieces and mandatory captures by jumping over opponent pieces. Draughts developed from alquerque. The name ‘draughts’ derives from the verb to draw or to move, whereas ‘checkers’ derives from the checkered board which the game is played on.

The most popular forms are English draughts, also called American checkers, played on an 8×8 checkerboard; Russian draughts, also played on an 8×8, and international draughts, played on a 10×10 board. There are many other variants played on 8×8 boards. Canadian checkers and Singaporean/Malaysian checkers (also locally known as dum) are played on a 12×12 board.

English draughts was weakly solved in 2007 by a team of Canadian computer scientists led by Jonathan Schaeffer. From the standard starting position, both players can guarantee a draw with perfect play.



Drawing is a form of visual art in which an artist uses instruments to mark paper or other two-dimensional surface. Drawing instruments include graphite pencils, pen and ink, various kinds of paints, inked brushes, colored pencils, crayons, charcoal, chalk, pastels, erasers, markers, styluses, and metals (such as silverpoint). Digital drawing is the act of using a computer to draw. Common methods of digital drawing include a stylus or finger on a touchscreen device, stylus- or finger-to-touchpad, or in some cases, a mouse. There are many digital art programs and devices.



A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. The content and function of dreams are not fully understood, although they have been a topic of scientific, philosophical and religious interest throughout recorded history. Dream interpretation is the attempt at drawing meaning from dreams and searching for an underlying message. The scientific study of dreams is called oneirology.



A drink (or beverage) is a liquid intended for human consumption. In addition to their basic function of satisfying thirst, drinks play important roles in human culture. Common types of drinks include plain drinking water, milk, coffee, tea, hot chocolate, juice and soft drinks. In addition, alcoholic drinks such as wine, beer, and liquor, which contain the drug ethanol, have been part of human culture for more than 8,000 years.



Driving is the controlled operation and movement of a vehicle, including cars, motorcycles, trucks, buses, and bicycles. Permission to drive on public highways is granted based on a set of conditions being met and drivers are required to follow the established road and traffic laws in the location they are driving. The word driving, has etymology dating back to the 15th century and has developed as what driving has encompassed has changed from working animals in the 15th to automobiles in 1888. Driving skills have also developed since the 15th century with physical, mental and safety skills being required to drive. This evolution of the skills required to drive have been accompanied by the introduction of driving laws which relate to not only the driver but the driveability of a car.



A duty (from “due” meaning “that which is owing”; Old French: deu, did, past participle of devoir; Latin: debere, debitum, whence “debt”) is a commitment or expectation to perform some action in general or if certain circumstances arise. A duty may arise from a system of ethics or morality, especially in an honor culture. Many duties are created by law, sometimes including a codified punishment or liability for non-performance. Performing one’s duty may require some sacrifice of self-interest.