General Information (D-H)
General Information (D-H)
The dada is an artistic and literary movement founded in 1915 in Zurich.
Dak was the east indian postal service. Properly a dak was a relay of men carrying letters, despatches and the like.
A dam is a structure constructed to hold back water and provide controlled flow for irrigation, storage and generation of electricity.
Damaskeening is the process of ornamenting iron and steel with designs produced by inlaying or incrusting with another metal such as gold or silver, by etching and the like.
Dance is a rhythmic movement of the body usually performed to music.
Data is information, especially that stored in a computer.
Daturine is the poisonous alkaloid found in the thorn-apple.
A day is the time taken for the earth to rotate once on its axis.
dBM is an identifier meaning "decibels referred to one milliwatt," the common reference point for power levels in telecommunications circuits.
Ddt is an insecticide discovered in 1939 by Paul Muller.
The decathlon is a 2 day olympic athletic event.
The decibel is the unit of measurement of sound intensity.
In electronics, the decibel is a unit of measurement representing the logarithmic a ratio of two voltages, currents or power levels; used in telecommunications to express transmission loss or gain; defined as one-tenth of a Bel, hence the appropriate notation is dB, shown here.
Deimos is one of the two moons of mars.
Delta is the 4th letter of the Greek alphabet.
The Devonian was the sixth geological period, 300,000,000 years ago. It marked the evolution of the insects and amphibians.
Dew is a precipitation in the form of moisture that collects on the ground after the temperature of the ground has fallen below the dew point temperature of the air in contact with the ground.
A didjeridu is a musical wind instrument developed by the Australian aborigines.
Digestion is the process of absorbing and distributing substances from ingested food to the body.
Digitalis is a drug derived from foxglove that increases heart efficiency.
A diode is a thermionic valve with two electrodes, or a semi conductor equivalent.
In a car, the distributor distributes electrical pulses to the spark plugs.
The term dixie refers to the southern states of the USA.
The domesday book is a record of the survey conducted in England in 1086 by officials of William the conqueror in order to assess taxes etc.
Dominoes is a game played with 28 rectangular spotted tiles. It originated in Italy in the 18th century.
The doppler effect is a change in observed wavelength due to relative motion between the source and observer.
Down's syndrome is a chromosomal abnormality.
The dram is a unit of the avoirdupois scale equivalent to 1.772 grams.
Draughts is a game played by two people on a board of 64 alternate black and white squares. Each player has twelve pieces, one set are black and the other red.
A dredger is a ship used for picking up rubbish from waterways.
A drill is a machine for boring holes in rock, metal or wood etc.
DWIM is an acronym for Do What I Mean. It is a term used in artificial intelligence for computer self-correcting of errors.
The earth is the third planet from the sun.
An eclipse is the passage of a celestial body through the shadow of another.
Ecstasy is an illegal drug synthesized from nutmeg oil and that reduces serotonin in the brain.
Eczema is an inflammatory skin disease.
EDAAS is an expert system that uses its knowledge of both the Toxic Substances Control Act (USA) and criteria for classifying information as confidential to help information specialists decide which information about the manufacturing and distribution of toxic chemicals must be released to the public and which information may be withheld for proprietary purposes. EDAAS was developed for the Ebvironmental Protection Agency in the USA using FORTRAN.
Effort is strenuous exertion.
An egg is a body specially developed in the females of animals which when impregnated by a male sperm developes into the young of the animal.
An element is a substance that cannot be split chemically into simpler substances.
The elgin marbles are a collection of ancient Greek sculptures assembled by the 7th earl of Elgin and brought to England in 1812
An embassy is an ambasador's residence.
An embryo is the offspring of an animal before it has been born or emerged from its egg.
Empyema is a pathological term describing a collection of pus in a cavity, especially applied to pus in the pleural cavity of the lung.
In physics, the term energy refers to an object's capacity to do work. This capacity is related to the strength of the flow of electrons in the object, or, in the case of potential energy, the amount of energy stored in the object. Thus, a powerful object such as the sun expells an enormous flow of electrons as solar energy, and a single atom of hydrogen contains the pathetic energy of a single electron orbiting its nucleus.
An enzyme is a biological catalyst that is not itself destroyed in the conversion process.
The Eocene was the fourteenth geological period, 50,000,000 years ago.
An epigram is a short witty or poignant poem.
An epigraph is an inscription carved on a stone, statue or coin.
Ergonomics is a discipline treating the consideration of human factors in design of the working environment and its components; intended to promote productivity and safety in the tools people work with.
Ester is an organic compound formed by the reaction between alcohol and acid with the elimination of water.
Etching is a process of putting a drawing or design onto a surface, usually metal, by corroding or scratching away the top surface so as to form the lines of the design.
Ethanoic acid is an organic fatty acid.
Ethanol is the chemical name for alcohol.
Ether is an anaesthetic. It has the formulae (c2h5)2o.
Ethernet was originally the trade name for a LAN developed by Xerox Corporation and later supported by Digital Equipment Corporation, Intel Corporation and Hewlett-Packard. It is now standardized as IEEE specification 802.3 .
Eugenics is the science of selective breeding to control physical and mental characteristics.
The farad is the unit of measurement of electrical capacitance.
Fathom is a nautical measurement, being 2 metres.
A fatty acid is an organic hydrocarbon with a carboxyl group at one end.
Feet is the plural of foot.
Fermentation is the breakdown of sugars by bacteria and yeast.
A ferret is a domesticated polecat.
Ferrous is a chemistry term refering to materials which contain iron.
Fiber Optics is a technology using light as a digital information bearer. Fiber optic cables ( light guides ) are a direct replacement for conventional wire, coaxial cable and many forms of radio, including microwave. Fiber optic lines actually cost less, occupy less space and provided far more transmission capacity than earlier methods, while providing superior quality due to virtual immunity to electrical interference.
A fife is a small flute originating from Switzerland.
The flugelhorn is a brass musical instrument.
Fluorescence is the process of emission of electromagnetic radiation resulting from the absorption of certain types of energy.
Fluoride is the salt of hydroflouric acid.
A foal is a young horse.
Fog is a cloud that collects at the surface of the earth.
Folic acid is a b vitamin, a lack of folic acid causes anaemia.
Fondant is a soft sweet made of flavoured sugar.
Foolscap is a regular paper size of 13.5 by 16.5 inches, so called because it was originally water-marked with a fool's head and cap.
The foot is a unit of the imperial scale of measurement of length equivalent to 12 inches or 30.48 centimetres.
The forecastle is a short deck in the forepart of a warship. In merchant ships it is the forepart of the ship where the sailors live.
A forelock is a wedge put through a hole in a bolt to keep the bolt in place.
The foresheets is the inner part of the bows of an open boat where the bowman stands.
Forest is a term properly applied to an extensive woodland or to a large tract of mingland woodland and open uncultivated land. In English law, a forest was a territory priveledged for game generally belonging to the sovereign and set aside for his recreation.
A forge is a blacksmith's fireplace or furnace for melting and refining metal.
Fortissimo is a musical term directing the singers to sing with the utmost strength and loudness.
A frail is a rush basket for packing figs and raisins.
Frangulin is a yellow crystallizable dye extracted from the bark of the alder. It is used to dye wool, silk and cotton.
Frankincense is an incense derived from the resin of the tree boswellia.
Friday is the fifth day of the week, the name derives from the Saxon Frige-doeg, the day sacred to Freya.
A Frith Gild was a Saxon voluntary association of neighbours for purposes of order and self-defence. They repressed theft, traced stolen cattle and indemnified parties robbed from a common fund raised by subscription of the members.
Fructose is a simple and very sweet sugar found in plant juices, fruit and honey.
Fruit is a botanical term for the mature ovary of a plant comprised of two parts, the pericarp and the seed.
Full Duplex is a communications term refering to a circuit which allows independent transmission information in both directions simultaneously. - Synonym: In wire telephony, 4 wire circuit.
The furlong is a unit of the imperial scale of measurement of length equivalent to 10 chains, 220 yards or 201.168 metres. The name fulong derives from furrow-length.
a fuse is a slow burning cord or other mechanism for delaying igniting a charge, such as a mine. Early fuses (slow-matches) were made of lightly twisted hemp dipped in potassium nitrate and ignited. Modern fuses may be electrical attached to a timer, or chemical in which an acid burns away a division in a container holding two chemicals which ignite when combined.
Gabilla is a Cuban measurement of tobacco. One gabilla is comprised of 36 or 40 leaves, 4 gabillas comprise 1 hand and 80 hands comprise 1 bale.
A gaff is a spar used in ships to extend the upper edge of fore-and-aft sails which are not set on stays.
Galactose is a sugar formed together with glucose when lactose is boiled in dilute acids.
A galaxy is a congregation of stars held together by gravity.
A galley-slave was a convict forced to work at the oar on board a galley, being chained to the deck. It was a punishment common in France untill 1748.
Gallic Acid (C7H6O5) is an acid which was first procured from the gall-nut by Scheele in 1786. It occurs in the seeds of the mango, acorn, tea, walnut and many other plants and is a decomposition product of tannic acid. It is used as an important black dye and is an ingredient in ink.
A galliot was a Dutch or Flemish ship used for transporting cargo in the late 19th and early 20th century. It had very rounded ribs and a flatish bottom, with a mizzen-mast placed near the stern, carrying a square main-sail and main-top-sail.
The gallon is a unit of capacity measurement equivalent to 4 quarts or 4.546 litres.
A galvanometer is an instrument for measuring an electric current by the defelction of a magnetic needle. Basically, it is comprised of a coil beneath a suspended magnetic needle. When electric current passes through the coil it sets up a magnetic field and attracts the needle, the stronger the current the more powerful the magnetic field and the more pronounced the needle's deflection from the earth's magnetic field.
Ganja was originally the Indian name for the dried shoots of the female hemp plant which have hashish resin on them. Today it is a Jamaican slang expression for cannabis and hashish.
Gas is a form of matter where the molecules move randomly.
A gauge is any scientific measuring instrument - for example, a wire gauge or a pressure gauge. The term is also applied to the width of a railroad or tramway track.
Gauss is the c.g.s. unit (symbol Gs) of magnetic induction or magnetic flux density, replaced by the SI unit, the tesla, but still commonly used. It is equal to one line of magnetic flux per square centimeter. The Earth's magnetic field is about 0.5 Gs, and changes to it over time are measured in gammas (one gamma equals 10-5 gauss).
Gemini is a sign of the zodiac.
In scientific classification, a genus is an assemblage of species posessing certain characteristics in common by which they are distinguished from others.
A geode is a round hollow nodule containing earthy matters, soemtimes quartz, sometimes agate. Geodes are found in most volcanic rocks and are formed by water depositing materials in the hollows of these rocks.
Geophagism is the practice of eating some kind of earthy matter, such as rock or chalk. It is most common amongst non-industrialised races, and was once thought to allay hunger. However, new evidence suggests that some peoples obtain valuable minerals in their diet from geophagism, as those minerals are not available in their normal food.
Geosynchronous Orbit is a position at an approximate altitude of 37 km above the Equator, where a velocity of about 2 km per hour in the same direction as Earth's rotation makes a satellite appear stationary over the Earth's surface. At such a point, ground-based microwave antennae can remain fixed and achieve linkage with transponders on board the satellite to produce a microwave relay between points as much as one-third of the way around the globe, or about 13 km; this concept first proposed by British physicist and science fiction writer Arthur C. Clarke in a 1947 publication.
In botany, the term geotropism refers to a disposition or tendancy to turn towards the earth.
Germanium is a metal element used in the manufacture of electronic semiconductors.
Gestation is the period which elapses between the impregnation of any mammal and the birth of the offspring. Gestation varies from 25 days in the case of the mouse to 620 days for an elephant, with the normal human gestation lasting 270 days (9 months).
The gibus is a type of opera hat named after its maker.
Gin is an alcoholic beverage flavoured with juniper.
Glass is a brittle substance made by fusing silica.
Glucic Acid is an acid produced by the action of alkalies on glucose or of acids on cane-sugar.
Glucose is a simple form of sugar with the formulae c6h12o6.
The glucosides are a group of carbon compounds occurring in plants, and characterized by the fact that on hydrolysis or saponification with dilute acids a sugar, usually glucose, is formed along with other products.
Gluten is a tough elastic substance of a greyish colour which becomes brown and brittle by drying, found in the flour of wheat and other grain. It contributes much to the nutritive quality of flour, and gives tenacity to its paste.
Glycine is a simple amino acid.
Golf is an outdoor game in which a small ball is struck with a club.
Gonidia are the secondary, green, sperical cells in the thallus of lichens which distinguish lichens from fungi.
Gonorrhoea is a specific contagious inflammation of the male urethra or the female vagina. It is a painful disease which may result in the chronic catarrh called gleet or may lead to stricture.
A gorget was a piece of body armour for the protection of the throat.
Gout is a disease marked by an excess of uric acid in the tissues.
The grain is a unit of measurement of the avoirdupois scale equivalent to 0.0648 grams.
Gram is the metric unit of mass; one-thousandth of a kilogram.
Gravel is a mixture of coarse sand and small water-worn stones. The term may also be applied to small water-worn stones on their own.
Gravity is the force of attraction between two objects resulting from their mass.
Greaves was body armour worn at the front of the lower part of the legs and buckled behind the leg.
A guitar is a stringed musical instrument played with the fingers or a plectrum.
Gules is the heraldic name for the colour red. It ranks highest among the colours.
Gum arabic is obtained from the acacia.
A gymnosperm is a plant with a naked seed, there being no proper ovary the seeds being fertilized by the pollen coming into direct contact with the foramen of the ovule without the intervention of a stigma.
Hackney Coach is the old name for a Hackney Carriage. They originated in London in 1625 when there were twenty of them available for hire. During the 19th century Hackney Coaches gave way to Hackney Cabs, which in turn have evolved into Hackney Carriages, now commonly called taxis.
Hafnium is a metal element occurring in zircon and used in nuclear reactors.
Hajj is the muslim pilgrimage to Mecca.
The half-hitch is a type of knot.
A hallmark is an official mark stamped on British gold, silver, and (from 1913) platinum, instituted in 1327 by the royal charter of London Goldsmiths in order to prevent fraud. After 1363, personal marks of identification were added. Now tests of metal content are carried out at authorized assay offices in London, Birmingham, Sheffield, and Edinburgh; each assay office has its distinguishing mark, to which is added a maker's mark, date letter, and mark guaranteeing standard.
Halogen is a particular group of elements with similar bonding properties.
HAM-RPM is a knowledge-based conversationalist that reasons with fuzzy information. It was developed at the University of Hamburg.
The hectare is the metric unit of area equal to 10,000 square meters (2.47 acres), symbol ha.
A helmet is an item of clothing designed to protect the head.
Hepatitis is an inflammatory disease of the liver.
The heptathlon is a 7 event athletics discipline.
Heraldry is the subject of armourial bearings.
A herb is a plant whose aerial parts do not remain above ground following the growing season.
Heroin is a powerful opiate analgesic.
Heuristic Dendral is an expert system, developed at Stanford University, that establishes the structure of a molecule given the molecule's atomic formula and mass spectrogram.
Hieroglyphics are signs comprising the picture writing of the ancient Egyptians.
An himation was a woollen cloak worn by the ancient Greeks.
Hockey is a game played with hooked sticks and a ball.
A hodometer was an early device for measuring the distance travelled by a vehicle.
A hoe is an instrument for cutting up weeds and loosening the earth in fields and gardens.
Honey is a sweet syrup made by bees from nectar.
Horsepower is an imperial unit of power, now replaced by the watt. It was first used by the engineer James Watt, who employed it to compare the power of steam engines with that of horses. In the UK, one horsepower is equal to 550 foot-pounds per second or 745.7 watts. In the USA this figure has been rounded to 746 watts, and in the metric system it is 735.5 watts.
A hospital is an institution for caring for the sick and injured.
A house is a building for human habitation.
A hoy was a small vessel, usually rigged as a sloop, and employed in carrying goods and passengers short distances coastwise, and sometimes in conveying goods and people to and from larger vessels and the shore.
Humus is partly decomposed organic matter. Found in soil.
The hundredweight (cwt) is a unit of measurement of the avoirdupois scale equivalent to 4 quarters, 112 pounds or 50.8 kilograms.
A hydrocarbon is a chemical containing only hydrogen and carbon.
Hydrocyanic Acid (Prussic Acid) was discovered by Scheele in 1782, and first prepared in a pure state by Gay-Lussac in 1811. It is found in the kernels of bitter almonds, peaches, apricots, plums, cherries and quinces and various plants leaves including beech, cherry and laurel. It is one of the most toxic substances known and is used to prepare cyanide.
A hydroxide is an inorganic compound containing one or more hydroxl groups.