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Apollo is one of the Olympian deities in classical Greek and Roman religion and Greek and Roman mythology. The national divinity of the Greeks, Apollo has been recognized as a god of archery, music and dance, truth and prophecy, healing and diseases, the Sun and light, poetry, and more. One of the most important and c... | Apollo |
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella, Prototheca and the diatoms, to multicellular form... | Algae |
The abacus (plural abaci or abacuses), also called a counting frame, is a calculating tool which has been used since ancient times. It was used in the ancient Near East, Europe, China, and Russia, centuries before the adoption of the Hindu-Arabic numeral system. The exact origin of the abacus has not yet emerged. It co... | Abacus |
An acid is a molecule or ion capable of either donating a proton (i.e., hydrogen ion, H+), known as a Brønsted–Lowry acid, or, capable of forming a covalent bond with an electron pair, known as a Lewis acid.
The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solu... | Acid |
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that Ame... | American National Standards Institute |
The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the num... | Atomic number |
Anatomy (Greek anatomē, 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inhere... | Anatomy |
Ambiguity is a type of meaning in which a phrase, statement or resolution is not explicitly defined, making several interpretations plausible. A common aspect of ambiguity is uncertainty. It is thus an attribute of any idea or statement whose intended meaning cannot be definitively resolved according to a rule or proce... | Ambiguity |
Asia () is Earth's largest and most populous continent, located primarily in the Eastern and Northern Hemispheres. It shares the continental landmass of Eurasia with the continent of Europe, and the continental landmass of Afro-Eurasia with Africa and Europe. Asia covers an area of , about 30% of Earth's total land are... | Asia |
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the W... | Atlantic Ocean |
An android is a humanoid robot or other artificial being often made from a flesh-like material. Historically, androids were completely within the domain of science fiction and frequently seen in film and television, but recent advances in robot technology now allow the design of functional and realistic humanoid robots... | Android (robot) |
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest physicists of all time. Einstein is best known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechani... | Albert Einstein |
In mathematics and computer science, an algorithm () is a finite sequence of well-defined instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. By making use of artificial intelligence, algor... | Algorithm |
Alexander Graham Bell (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist, and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and Telegraph Company (AT&T) in 1885.
Bell's father, grandfather, and brother had ... | Alexander Graham Bell |
Anatolia, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The region is bounded by the Turkish Straits to the northwest, the Black Sea to the north, the Armenian Highlands to the east, the Mediterra... | Anatolia |
Apple Inc. is an American multinational technology company that specializes in consumer electronics, software and online services. Apple is the largest information technology company by revenue (totaling in 2021) and, as of January 2021, it is the world's most valuable company, the fourth-largest personal computer ven... | Apple Inc. |
Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in the Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 2... | Argon |
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industr... | Arsenic |
Antimony is a chemical element with the symbol Sb (from ) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name kohl... | Antimony |
Actinium is a chemical element with the symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name emanium; the element got its name by being wrongly identified with a substance André-Louis Debierne found in 1899 and called actinium. Actinium gave the name to the actin... | Actinium |
Americium is a synthetic radioactive chemical element with the symbol Am and atomic number 95. It is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas.
Americium was first produced in 1944 by the group of G... | Americium |
Astatine is a chemical element with the symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. A sample... | Astatine |
An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics—as if they w... | Atom |
Aluminium (or aluminum in American English and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the ... | Aluminium |
An axiom, postulate, or assumption is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. The word comes from the Ancient Greek word (), meaning 'that which is thought worthy or fit' or 'that which commends itself as evident'.
The term has subtle differen... | Axiom |
Augusta Ada King, Countess of Lovelace (née Byron; 10 December 1815 – 27 November 1852) was an English mathematician and writer, chiefly known for her work on Charles Babbage's proposed mechanical general-purpose computer, the Analytical Engine. She was the first to recognise that the machine had applications beyond pu... | Ada Lovelace |
The Alps are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across eight Alpine countries (from west to east): France, Switzerland, Monaco, Italy, Liechtenstein, Austria, Germany, and Slovenia.
The Alpine arch generally extends from Nice on the western Med... | Alps |
April is the fourth month of the year in the Gregorian calendar, the fifth in the early Julian, the first of four months to have a length of 30 days, and the second of five months to have a length of less than 31 days.
April is commonly associated with the season of autumn in parts of the Southern Hemisphere, and spri... | April |
August is the eighth month of the year in the Julian and Gregorian calendars, and the fifth of seven months to have a length of 31 days. Its zodiac sign is Leo and was originally named Sextilis in Latin because it was the 6th month in the original ten-month Roman calendar under Romulus in 753 BC, with March being the f... | August |
In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl functional group (−OH) bound to a saturated carbon atom. The term alcohol originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. An importan... | Alcohol (chemistry) |
Ibn Sina (), also known as Abu Ali Sina (), Pour Sina (), and often known in the West as Avicenna (; – June 1037), was a Persian polymath who is regarded as one of the most significant physicians, astronomers, thinkers and writers of the Islamic Golden Age, and the father of early modern medicine. Sajjad H. Rizvi has ... | Avicenna |
Augustin-Jean Fresnel ( ; ; or ; ; 10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular theory, from the late 1830s until the end of the 19th century. He is perha... | Augustin-Jean Fresnel |
In mathematics, an automorphism is an isomorphism from a mathematical object to itself. It is, in some sense, a symmetry of the object, and a way of mapping the object to itself while preserving all of its structure. The set of all automorphisms of an object forms a group, called the automorphism group. It is, loosely ... | Automorphism |
Artificial intelligence (AI) is intelligence demonstrated by machines, as opposed to natural intelligence displayed by animals including humans. Leading AI textbooks define the field as the study of "intelligent agents": any system that perceives its environment and takes actions that maximize its chance of achieving i... | Artificial intelligence |
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity, and luster, but may have properties that differ from those of the... | Alloy |
Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned with the way in which electrons are arranged around the nucleus and
the proces... | Atomic physics |
In atomic theory and quantum mechanics, an atomic orbital is a mathematical function describing the location and wave-like behavior of an electron in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus. The term atomic orbit... | Atomic orbital |
Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation ... | Alan Turing |
Ada is a structured, statically typed, imperative, and object-oriented high-level programming language, extended from Pascal and other languages. It has built-in language support for design by contract (DbC), extremely strong typing, explicit concurrency, tasks, synchronous message passing, protected objects, and non-d... | Ada (programming language) |
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two. An alpha particle is identical to the nucl... | Alpha decay |
In mathematics, the term "almost all" means "all but a negligible amount". More precisely, if is a set, "almost all elements of " means "all elements of but those in a negligible subset of ". The meaning of "negligible" depends on the mathematical context; for instance, it can mean finite, countable, or null.
In con... | Almost all |
In particle physics, every type of particle is associated with an antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron is the antielectron (which is often referred to as positron). While the electron has a negative electric charge, t... | Antiparticle |
The Andes, Andes Mountains or Andean Mountains () are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S - 20°S latitude), and has an average height of about . The Andes extend from north to south thr... | Andes |
Ammonia is a compound of nitrogen and hydrogen with the formula NH3. A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs o... | Ammonia |
In computer programming, assembly language (or assembler language), sometimes abbreviated asm, is any low-level programming language in which there is a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per ... | Assembly language |
In the ancient Greek myths, ambrosia (, ) is the food or drink of the Greek gods, often depicted as conferring longevity or immortality upon whoever consumed it. It was brought to the gods in Olympus by doves and served by either Hebe or Ganymede at the heavenly feast.
Ambrosia is sometimes depicted in ancient art as ... | Ambrosia |
Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects. Amber is used in jewelry. It has also been used as a healing agent in folk medicine.
There are fi... | Amber |
The terms (AD) and before Christ (BC) are used to label or number years in the Julian and Gregorian calendars. The term is Medieval Latin and means "in the year of the Lord", but is often presented using "our Lord" instead of "the Lord", taken from the full original phrase "anno Domini nostri Jesu Christi", which tra... | Anno Domini |
APL (named after the book A Programming Language) is a programming language developed in the 1960s by Kenneth E. Iverson. Its central datatype is the multidimensional array. It uses a large range of special graphic symbols to represent most functions and operators, leading to very concise code. It has been an important... | APL (programming language) |
The Apollo program, also known as Project Apollo, was the third United States human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which succeeded in preparing and landing the first humans on the Moon from 1968 to 1972. It was first conceived during Dwight D. Eisenhower's a... | Apollo program |
Aspirin, also known as acetylsalicylic acid (ASA), is a medication used to reduce pain, fever, or inflammation. Specific inflammatory conditions which aspirin is used to treat include Kawasaki disease, pericarditis, and rheumatic fever.
Aspirin given shortly after a heart attack decreases the risk of death. Aspirin is... | Aspirin |
Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientific knowledge, and it has been characterized as quackery. There is a range of ac... | Acupuncture |
In algorithmic information theory (a subfield of computer science and mathematics), the Kolmogorov complexity of an object, such as a piece of text, is the length of a shortest computer program (in a predetermined programming language) that produces the object as output. It is a measure of the computational resources n... | Kolmogorov complexity |
Ḥasan Ibn al-Haytham, Latinized as Alhazen (; full name ; ), was a Muslim Arab mathematician, astronomer, and physicist of the Islamic Golden Age. Referred to as "the father of modern optics", he made significant contributions to the principles of optics and visual perception in particular. His most influential work i... | Ibn al-Haytham |
Ambergris ( or , , ), ambergrease, or grey amber, is a solid, waxy, flammable substance of a dull grey or blackish colour produced in the digestive system of sperm whales. Freshly produced ambergris has a marine, fecal odor. It acquires a sweet, earthy scent as it ages, commonly likened to the fragrance of rubbing alc... | Ambergris |
Alexander Selkirk (167613 December 1721) was a Scottish privateer and Royal Navy officer who spent four years and four months as a castaway (1704–1709) after being marooned by his captain, initially at his request, on an uninhabited island in the South Pacific Ocean. He survived that ordeal, but succumbed to tropical i... | Alexander Selkirk |
The acre is a unit of land area used in the imperial and US customary systems. It is traditionally defined as the area of one chain by one furlong (66 by 660 feet), which is exactly equal to 10 square chains, of a square mile, 4,840 square yards, or 43,560 square feet, and approximately 4,047 m2, or about 40% of a hec... | Acre |
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A lim... | Antibiotic |
Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element: the atoms of the element are bonded together in a different manner.
For example... | Allotropy |
Baron Augustin-Louis Cauchy (; ; 21 August 178923 May 1857) was a French mathematician, engineer, and physicist who made pioneering contributions to several branches of mathematics, including mathematical analysis and continuum mechanics. He was one of the first to state and rigorously prove theorems of calculus, reje... | Augustin-Louis Cauchy |
Alternative medicine is any practice that aims to achieve the healing effects of medicine, but which lacks biological plausibility and is untested, untestable or proven ineffective. Complementary medicine (CM), complementary and alternative medicine (CAM), integrated medicine or integrative medicine (IM), and holistic ... | Alternative medicine |
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancesto... | Adaptive radiation |
Agarose gel electrophoresis is a method of gel electrophoresis used in biochemistry, molecular biology, genetics, and clinical chemistry to separate a mixed population of macromolecules such as DNA or proteins in a matrix of agarose, one of the two main components of agar. The proteins may be separated by charge and/or... | Agarose gel electrophoresis |
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. Antibiotic resistance is a subset of AMR, that applies specifically to bacteria that become resistant to antibiotics.
Infections due to AMR cause millions of deaths each year. Infections caused ... | Antimicrobial resistance |
The word aeon , also spelled eon (in American and Australian English), originally meant "life", "vital force" or "being", "generation" or "a period of time", though it tended to be translated as "age" in the sense of "ages", "forever", "timeless" or "for eternity". It is a Latin transliteration from the koine Greek wo... | Aeon |
Sir Andrew John Wiles (born 11 April 1953) is an English mathematician and a Royal Society Research Professor at the University of Oxford, specializing in number theory. He is best known for proving Fermat's Last Theorem, for which he was awarded the 2016 Abel Prize and the 2017 Copley Medal by the Royal Society. He w... | Andrew Wiles |
Avionics (a blend of aviation and electronics) are the electronic systems used on aircraft, artificial satellites, and spacecraft. Avionic systems include communications, navigation, the display and management of multiple systems, and the hundreds of systems that are fitted to aircraft to perform individual functions. ... | Avionics |
Asterix or The Adventures of Asterix ( or , ; "Asterix the Gaul") is a Bande dessinée comic book series about Gaulish warriors, who adventure around the world and fight the Roman Republic, with the aid of a magic potion, during the era of Julius Caesar in an ahistorical telling of the time after the Gallic Wars. The se... | Asterix |
In organic chemistry, hydrocarbons (compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. aleiphar, fat, oil). Aliphatic compounds can be saturated, like hexane, or unsaturated, like hexene and hexyne. Open-chain compounds, whether straight or b... | Aliphatic compound |
Abiotic stress is the negative impact of non-living factors on the living organisms in a specific environment. The non-living variable must influence the environment beyond its normal range of variation to adversely affect the population performance or individual physiology of the organism in a significant way.
Where... | Abiotic stress |
Sir Arthur Stanley Eddington (28 December 1882 – 22 November 1944) was an English astronomer, physicist, and mathematician. He was also a philosopher of science and a populariser of science. The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object... | Arthur Eddington |
Ayahuasca is a South American (pan-Amazonian) psychoactive brew used both socially and as ceremonial spiritual medicine among the indigenous peoples of the Amazon basin. It is a psychedelic and entheogenic mixed drink brew commonly made out of the Banisteriopsis caapi vine, the Psychotria viridis shrub or a substitute,... | Ayahuasca |
Anointing of the sick, known also by other names, is a form of religious anointing or "unction" (an older term with the same meaning) for the benefit of a sick person. It is practiced by many Christian churches and denominations.
Anointing of the sick was a customary practice in many civilizations, including among the... | Anointing of the sick |
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a p... | Antibody |
Albrecht Dürer (; ; ; 21 May 1471 – 6 April 1528), sometimes spelled in English as Durer (without an umlaut) or Duerer, was a German painter, printmaker, and theorist of the German Renaissance. Born in Nuremberg, Dürer established his reputation and influence across Europe in his twenties due to his high-quality woodcu... | Albrecht Dürer |
Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes. Qualitative analysis identifies analytes, while qu... | Analytical chemistry |
An analog computer or analogue computer is a type of computer that uses the continuous variation aspect of physical phenomena such as electrical, mechanical, or hydraulic quantities (analog signals) to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discre... | Analog computer |
Apoptosis (from Ancient Greek ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA ... | Apoptosis |
ATM or atm often refers to:
Atmosphere (unit) or atm, a unit of atmospheric pressure
Automated teller machine, a cash dispenser or cash machine
ATM or atm may also refer to:
Computing
ATM (computer), a ZX Spectrum clone developed in Moscow in 1991
Adobe Type Manager, a computer program for managing fonts
Accel... | ATM |
Asynchronous Transfer Mode (ATM) is a telecommunications standard defined by ANSI and ITU-T (formerly CCITT) for digital transmission of multiple types of traffic, including telephony (voice), data, and video signals in one network without the use of separate overlay networks. ATM was developed to meet the needs of the... | Asynchronous Transfer Mode |
Amphetamine (contracted from alpha-methylphenethylamine) is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered in 1887 and exists as two enantiomers: levoamphetamine and dextroamphetamine. Ampheta... | Amphetamine |
Automated theorem proving (also known as ATP or automated deduction) is a subfield of automated reasoning and mathematical logic dealing with proving mathematical theorems by computer programs. Automated reasoning over mathematical proof was a major impetus for the development of computer science.
Logical foundations... | Automated theorem proving |
Agent Orange is a herbicide and defoliant chemical, one of the "tactical use" Rainbow Herbicides. It is widely known for its use by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. It is a mixture of equal parts of two herbicides, 2,4,5-T and 2... | Agent Orange |
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0; the years before that are designated with negative numbers and the years after that are designated with positive numbers. Astronomers use the Julian calendar for years before ... | Astronomical year numbering |
Ab urbe condita ( 'from the founding of the City'), or anno urbis conditae (; 'in the year since the city's founding'), abbreviated as AUC or AVC, express a date in years since 753 BC, the traditional founding of Rome. It is an expression used in antiquity and by classical historians to refer to a given year in Ancien... | Ab urbe condita |
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants appear in the fossil record across the globe in considerable diversity during the latest Early Cretaceous and early Late Cretaceous, suggesting an earlier origin. Ants evolved from vespoi... | Ant |
See also, Abatement.
Abated, an ancient technical term applied in masonry and metal work to those portions which are sunk beneath the surface, as in inscriptions where the ground is sunk round the letters so as to leave the letters or ornament in relief.
References
Construction
Masonry | Abated |
Atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES) is a spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. Atomic absorption spectroscopy is based on absorption of light by fr... | Atomic absorption spectroscopy |
The Anatomical Therapeutic Chemical (ATC) Classification System is a drug classification system that classifies the active ingredients of drugs according to the organ or system on which they act and their therapeutic, pharmacological and chemical properties. Its purpose is an aid to monitor drug use and for research to... | Anatomical Therapeutic Chemical Classification System |
Parallel ATA (PATA), originally , also known as ATA or IDE is standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and CD or DVD drives. The connection is used for storage devices such as hard disk drives, floppy disk drives... | Parallel ATA |
Astrobiology, known as exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investigates the deterministic conditions and contingent events with which life arises, distributes, ... | Astrobiology |
Aerodynamics, from Greek ἀήρ aero (air) + δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics.The term aerodynamics is often used synonymously with gas d... | Aerodynamics |
The Aberdeen Bestiary (Aberdeen University Library, Univ Lib. MS 24) is a 12th-century English illuminated manuscript bestiary that was first listed in 1542 in the inventory of the Old Royal Library at the Palace of Westminster. Due to similarities, it is often considered to be the "sister" manuscript of the Ashmole Be... | Aberdeen Bestiary |
In the field of artificial intelligence, the most difficult problems are informally known as AI-complete or AI-hard, implying that the difficulty of these computational problems, assuming intelligence is computational, is equivalent to that of solving the central artificial intelligence problem—making computers as inte... | AI-complete |
In condensed matter physics and materials science, an amorphous (from the Greek a, "without", and morphé, "shape, form") or non-crystalline solid is a solid that lacks the long-range order, which is a characteristic of a crystal. In some older articles and books, the term was used synonymously with glass. Today, howeve... | Amorphous solid |
Albinism is a congenital condition characterized in humans by the partial or complete absence of pigment in the skin, hair and eyes. Albinism is associated with a number of vision defects, such as photophobia, nystagmus, and amblyopia. Lack of skin pigmentation makes for more susceptibility to sunburn and skin cancers.... | Albinism in humans |
In computability theory, the Ackermann function, named after Wilhelm Ackermann, is one of the simplest and earliest-discovered examples of a total computable function that is not primitive recursive. All primitive recursive functions are total and computable, but the Ackermann function illustrates that not all total co... | Ackermann function |
The Association for Computing Machinery (ACM) is a US-based international learned society for computing. It was founded in 1947 and is the world's largest scientific and educational computing society. The ACM is a non-profit professional membership group, claiming nearly 100,000 student and professional members . Its h... | Association for Computing Machinery |
In chemistry, an alkali (; from ) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline is commonly, and alkalescent less often, used in English as a synonym f... | Alkali |
An anemometer is a device used for measuring wind speed and direction. It is also a common weather station instrument. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed instrument used in meteorology. The first known description of an anemometer was given by Leon ... | Anemometer |
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