General Information (D-E)

D Layer
The D Layer is the lowest region of ionized gas in the
ionosphere. It exists only during the hours of daylight, at an altitude of about 70 km.

In the Penal Code, dacoity is defined as organised banditry by 5 or more persons. The word derives from the Hindustani word for a robber,

The dada is an artistic and literary movement founded in 1915 in

Daguerreotype was the earliest process of photographic
reproduction, and was so called after its inventor Louis Daguerre. A copper plate, polished and silvered, was sensitised by exposure to iodine vapour, and so coated with a fine layer of silver iodide. It was then exposed in a camera, like modern photographic film, but with a longer exposure time. It was afterwards removed and treated with mercury vapour, the mercury attaching itself to those areas which had been most exposed to light and settling there in a density proportionate to the strength of the light.

A dahabiyeh is a broad, shallow-draught vessel with a sharp prow and sails used for conveying passengers on the

Dak was the east Indian postal service. Properly a dak was a relay of men carrying letters, despatches and the like.

Dakin's Solution
Solution is a disinfectant solution containing sodium hydrochlorite, rendered neutral by the addition of boric acid as a buffer. The disinfectant action of the solution is very rapid, but it has the disadvantage of being unstable and does not keep for more than about a week.

A dalmatic is a sleeveless embroidered vestment worn by deacons in the
Roman Church and the High Church section of the Anglican Church during the celebration of High Mass and at processions.

A dam is a structure constructed to hold back
water and provide controlled flow for irrigation, storage and generation of electricity.

Damask is a material of
silk, linen, etc., with a raised of flat pattern woven into it, and shading alternately light and dark, according to the angle of view. The name derives from Damascus where in the 12th century silk fabrics of a similar pattern were made.

Damaskeening is the process of ornamenting
iron and steel with designs produced by inlaying or encrusting with another metal such as gold or silver, by etching and the like.

Dammar Gum
Dammar Gum is a naturally occurring gum obtained from coniferous
trees that grow in the East Indies and Philippines. Dammar gum is soluble in turpentine and is employed in varnish and lacquers.

Dance is a rhythmic movement of the body usually performed to music.

Danegeld was a tax first levied by Ethelred II for the purpose of raising enough money to buy off the Danes and prevent their periodic invasions of
England in the 10th century.

Dark Ages
The Dark Ages were the five or six centuries following the fall of the west
Roman Empire, after the civilisation of Rome, based on unity and inter-communication had been destroyed by repeated barbarian invasions.

Dark Room
A dark room is a specially darkened studio used for photographic work. As much of the material used in photography is sensitive to
light, many operations must be conducted in darkness.

Darlington Pair
Darlington Pair is an electronic circuit using two transistors with the collectors connected together and the emitter of the first directly coupled to the base of the second. This configuration gives very high gains equal to the gains of the two individual transistors multiplied together.

Data is information, especially that stored in a

Daturine is the
poisonous alkaloid found in the thorn-apple.

Davis cup
The Davis cup is a
tennis tournament.

A day is the time taken for the
earth to rotate once on its axis. Astronomically a day is reckoned to begin at noon; for civil purposes, at midnight.

Daylight Saving Time
Daylight Saving
Time is a device for the better utilisation of daylight by a temporary abandonment of sun-time in summer. It was first suggested in 1907 by William Willett, and implemented in 1916 in order to procure economy in light and fuel as an Act which provided that all clocks be put forward one hour for a period of about 5.5 months during the summer in England. This emergency measure was perpetuated by an Act of 1925, and adopted by many other European countries.

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.

De Haeretico Comburendo
De Haeretico Comburendo was a statute of 1401 against the Lollards. By it, a heretic convicted before a spiritual tribunal and refusing to recant was to be burned.

Decahydro-naphthalene is
naphthalene which has been completely reduced by catalytic hydrogenation. It is a colourless liquid with a pleasant odour and the formulae C10H18 used as a solvent and cleaning-agent.

Decalin was a commercial name for

The decathlon is a 2
day Olympic athletic event.

Deceleration is the rate at which a moving body decreases in

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.

Declaration of Independence
The Declaration of
Independence was made in 1776 by the 13 English colonies in North America breaking away from all allegiance to the British Crown. The Declaration was mainly the work of Thomas Jefferson. Already in December 1775 the Congress had declared itself independent of the English parliament and by this declaration had repudiated allegiance to the Crown.

Declaration of Indulgence
The Declaration of Indulgence in 1687 was a proclamation by
James II repealing all religious tests and penal laws against Roman Catholics and Dissenters. The Declaration was republished in 1688 and ordered to be read in the churches. Their refusal to do this led to the trial of the Seven Bishops, who were acquitted.

Declaration of Paris
The Declaration of
Paris in 1856 adopted with the Treaty of Paris to establish four principles of international law: 1) Privateering to be abolished; 2) the neutral flag might cover enemy goods except contraband of war; 3) neutral goods, except contraband of war, not to be subject to capture under an enemy's flag; 4) blockades, to be binding, must be effective, i.e. maintained by a sufficient force.

Strictly speaking, a decoy is either a tame or artificial
duck, so placed as to lure wild ducks within gunshot range. The term is widely applied to any means by which a person or animal is lured into a trap.

In law, defamation is a false statement tending to expose another person to hatred, contempt or ridicule, or to injure him in his
trade or profession. Mere insult is not sufficient.

Defence of the Realm Acts
The Defence of the Realm
Acts (DORA) were a series of Acts passed during and after the Great War in Britain conferring on the King in Council the power to take extra-ordinary measures for the defence of the realm. Perhaps the most unpopular Act was the limitation of the times during which intoxicants could be sold, commonly known as the licensing hours and not relaxed until the 1990s.

Deimos is one of the two moons of

A dekatron is a gas-filled cold-cathode electron tube, having a central
anode and ten effective cathodes, used in electronic counting circuits.

A substance is deliquescent when it has an affinity for
water strong enough to absorb it from the atmosphere in large quantities. Typically deliquescent salts are calcium chloride and ammonium nitrate.

see "

Delta is the 4th letter of the
Greek alphabet. In geography, a delta is an alluvial triangular deposit formed at diverging mouths of a river.

Delta Metal
Delta Metal is a variety of brass containing 55 percent copper, 41 percent zinc and 4 percent various other metals.

Delta Rays
Delta rays are a stream of electrons moving at a relatively low velocity.

A denaturant is a substance added to intoxicating liquids such as
alcohol, so that while they are rendered unfit to drink are still usable in industry. However, the theory behind their use fails to appreciate the desperation of some alcoholics, and the drinking of methylated spirits despite being made more dangerous by the addition of toxic denaturants, is still just as widespread, but with even more injury occurring to those who consume it.

Density is the
mass of a substance in relation to its volume, and usually expressed as the weight in grams of 1 cubic centimetre. Since volume enters into this dimension, and volume varies with temperature, it is essential that the temperature at which the measurement was taken is revealed when stating the density of a substance.

In architecture, a dentil is one of a series of small square projecting blocks in the moulding of a cornice. They were originally employed as a decorative representation of the beam-ends of a wooden roof, the term has been extended to apply to objects made of wood.

Dentistry is a branch of medical science concerned with the care of the teeth, and including the treatment of unsound teeth, the prevention of dental diseases and the manufacture of artificial teeth. Although practised in ancient
Egypt, it was not until the 19th century that dentistry became a subject for serious scientific research and considered a branch of medicine.

Denudation is a geological term for the wearing away of the
earth's surface by the various agents - rain, frost, rivers, glaciers and ocean waves, each agent exhibiting a different kind of erosion.

In old
English law, deodand was a term denoting anything which had caused the death of a person, accidentally or otherwise, and was thereupon forfeited to the crown to be put to some good use.

A depilatory is a substance which has the power to remove hair other than by cutting it. The term is generally applied to cosmetic hair removers.

In geology, deposition is a term applied to the laying-down of material by the various agents, such as wind, rivers, lakes, oceans and glaciers, each
deposit exhibiting distinct characteristics.

Derating is a scheme to encourage agriculture and industry by relieving them of a portion or the whole rates normally payable. the principle was introduced by Winston Churchill in the Budget of 1928 and incorporated in the Local Government (Derating) Act of 1929. The Act relieved agricultural land of the whole, and productive industry of three-quarters, of rates previously levied, and substituted therefor a lump sum government grant, distributed among the local authorities. The effect of derating was obscured by the subsequent industrial depression.

Dermatitis is a term applied to many kinds of inflammation of the

A desiccator is an apparatus used mainly in the laboratory, by which substances can be thoroughly freed from

A desk is a flat or sloping table used for
reading, writing or drawing, with or without legs. In the Middle Ages a plank was generally used.

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.

Dextrin is a sticky mixture of water-soluble products, an intermediate stage in the hydrolysis of
starch into sugars. It was formerly marketed as an adhesive under the name of "British Gum".

A dialect is a characteristic manner of speech confined to a particular locality and differing, to a greater or lesser extent, from the standard speech of the country. The distinction between dialect and language is one of expediency rather than science.

Diallyl barbituric acid
Diallyl barbituric
acid is a colourless crystalline organic compound used in medicine as a soporific.

Dialogue is a form of literature consisting of a conversation between two or more characters and so having considerable affinities with drama.

Diastase is a substance which occurs in
saliva and in the secretions of the pancreas. It is an enzyme which has the power to break down starch with the formation of sugars.

Diathermy is a therapeutic treatment in which heat is produced in body
tissues by passing high-frequency electric currents through them.

Diazo Compounds
Diazo Compounds are a group of
organic compounds characterised by the presence of the group -N2-. They are prepared by means of the diazo reaction, which consists in treating a primary aromatic amine with nitrous acid. Salts of this type are used in the production of dyestuffs.

Dichroic Mirror
A Dichroic mirror is a mirror consisting of a
glass plate on which is deposited a very thin film of metal. It will transmit light of a particular colour, but reflects light of other colours.

A didjeridu is a musical wind instrument developed by the Australian aborigines.

Die-casting is a method of casting metals by forcing them under pressure into moulds of a strong and permanent character capable of repeated use. Die-casting is said to have originated with the advent of printing, which necessitated the production of sharply cast types in large numbers.

Dielectric is the name given to an electric insulating material.

Dietetics is the study of food in relation to the promotion and maintenance of health. Despite the attempts of some authors to claim it is a new science, it has been known and practised for centuries, and the term dietetics precedes the Second World War.

Diethyl-barbituric acid
see "

Diffusionism is the theory that
human culture was spread by degrees by outward expansion from a single source, as opposed to the view that cultures are developed independently and are only diffused when a particular people develops a more or less permanent type of culture which is well in advance of that of neighbouring peoples and becomes impressed upon the latter.

Diflunisal is a drug used to treat mild to moderate pain and
osteoarthritis It has the possible side effects of: dizziness,
insomnia, headache, ringing in the ears, nausea,
gastrointestinal pain, diarrhea, vomiting, constipation, excess wind,
rash and itching.

Digamma was an ancient
Greek letter, which was already obsolete in classical times, and so called because its form resembled a double gamma. It was pronounced like an English w.

see "

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.

Dihydroxysuccinic acid
see "
Tartaric Acid"

A dilatometer is an apparatus used to measure changes in volume of solids. The
solid is placed in a glass bulb with a capillary tube, and the bulb and part of the tube are filled with a liquid which is without action on the solid. By observing the liquid's position in the tube, changes in the volume of the solid may be measured.

see "

Dimethylmethane diethylsulphone
see "

Dimity is a strong
cotton material with raised patterns, usually white, used for curtains and especially bed-curtains during the 18th and 19th centuries.

Dimorphism is a special case of polymorphism; the
state when the same substance can appear in two different crystalline forms. Ice for example can exist as ordinary light ice, or if frozen below minus 20 degrees and subjected to high pressure forms dense ice which is heavier than water.

A dinghy is a small Indian river-boat. The term was adopted for the small row-boat attached to a larger vessel for general purposes and today is used to describe any small row-boat.

A diode is a thermionic
valve with two electrodes, or a semi-conductor equivalent. It presents a high resistance one way around and a low resistance the other.

Diphenyl is an alternative name for
Phenyl benzene.

Diphtheria is a disease produced by the Klebs-Loeffler bacillus. Diphtheria is unusual in that after infection it does not spread in the body, but the bacillus remains at the site of its primary invasion. This site may be the fauces in front of the throat, or the
larynx. Very occasionally the bacillus gains access to a wound and gives rise to "wound diphtheria". In any case, the disease multiplies and produces a membrane which in the case of the laryngeal type may produce death by mechanical blockage of the air passage. The chief danger however lies in the toxins discharged by the bacillus which enter the blood system and affect the muscles in particular, giving rise to a danger of heart-attacks.

Dipole aerial
A dipole
aerial is an aerial consisting of two straight conductors mounted in line, the connection being made to the two inner ends.

Dipsomania is the technical term for alcoholism, produced by taking large quantities of
alcohol over a long period of time.

Dipyridamole is a coronary vasodilator drug used to reduce the frequency and
intensity of angina attacks and prevents
blood clots after heart surgery.

A disinfectant is a substance applied to the outside of the body, or to non-living material in order to kill any micro-organisms which may be present.

Disopyramide is an antiarrhythmic drug used to correct
heart rhythm
disorders which it does by delaying nerve impulses to the heart to
regulate the heartbeat.

Disorderly House
In law, a Disorderly
House is a house where persons meet for unlawful purposes, such as a brothel or gaming-house.

Displacement is the size of a
ship as measured by the actual weight of water which it displaces when afloat.

Dissection is the process of cutting away and separating parts of a body, whereby its formation and the relationships of its parts can be observed.

In a car, the distributor distributes electrical pulses to the spark plugs.

A diuretic is a medicine which increases the flow of
urine by acting on the kidneys either directly or secondarily through the blood or nervous system.

The term Dixie refers to the southern states of the

Doctor Wind
The Doctor Wind is a prevailing daytime breeze which blows onto the island of
Jamaica from the sea.

Dog Days
dog days are the hottest part of the year in Europe, being part of July and August. Formerly the dog days were specifically the period during which Sirius, the dog-star, rises approximately with the sun.

Domesday Book
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.

Doomsday book
see "
domesday book"

Doppler effect
The Doppler effect is a change in observed wavelength due to relative motion between the source and observer.

see "
Defence of the Realm Acts"

Down's syndrome
Down's syndrome is a chromosomal abnormality.

Dragon's Blood
Dragon's Blood is a red resin obtained from the fruits of several East Indian trees. The material is a solid, soluble in alcohol and fatty oils, and used in the manufacture of furniture polishes, for staining marble and in some forms of printing.

The dram is a unit of the
avoirdupois scale equivalent to 1.772 grams.

see "

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

A dredger is a
ship used for picking up rubbish from waterways and removing materials from beneath the surface of the water.

A drill is a machine for boring holes in
rock, metal or wood etc. Drill bits were greatly improved from the invention in the 18th century of the twist drill, consisting of a rod of steel with a deep channel cut into it in a spiral, and the end ground off at an obtuse angle to give two cutting edges and a very short point.

Dropsy is an accumulation of serous fluid in the body cavities or
tissues. Serum is normally exuded through the walls of the small blood-vessels, part of it being absorbed by the veins and lymphatic vessels and returned to the blood. Dropsy arises when the serum is not absorbed sufficiently or is exuded in abnormal quantities, and is therefore more a symptom of some other disturbance than a disease in itself.

Dry Ice
Ice is a commercial name for solidified carbon dioxide, often used as a coolant. It is called dry ice because as it melts, it gives off a gas rather than a liquid, and so appears dry.

Dry Joint
In electrical terms, a dry
joint is a soldered joint which, due to insufficient heating or lack of sufficient flux during the soldering operation, the solder has not adhered to the metals to be joined, thus producing a joint which is weak mechanically and of high electrical resistance.

Dry Rot
Dry Rot is a name given to the fungus Merulius lacrymans which attacks wood in houses. The name derives from the dry appearance of the wood after decay.

A dry-dock is a dock from which the
water may be emptied to allow of convenient and expeditious ship-repairs.

The dulcimer was a musical instrument consisting of a resonance-board over which wires were stretched, these being struck by hammers held by the performer.

The Duma was the lower
House of the Russian Imperial Parliament. It was created in 1905 by the Constitution granted by Tsar Nicholas II, and replaced in 1917 by the Soviet system.

A dungeon is an underground prison, originally in the keep of a
Norman castle.

Duralumin is an
alloy of aluminium, copper and magnesium, with traces of other metals. Typically duralumin is comprised of 94.4 percent aluminium, 4.5 percent copper, 0.95 percent magnesium and 0.76 percent manganese. If properly tempered it has an extremely high tensile strength and is used in aircraft construction.

In law, duress is the unlawful constraint or compulsion of a person by physical
action or threats.

Dutch East India Company
The Dutch
East India Company was a chartered company formed in 1595 and granted a monopoly of trade in the Pacific and Indian Ocean in 1602. It was dissolved in 1798 and its territories taken over by the Dutch Government.

Dutch West India Company
The Dutch
West India Company was a chartered company granted a monopoly of trade in the Atlantic Ocean with America and Africa by the Dutch Government in 1621.

DWIM is an
acronym for Do What I Mean. It is a term used in artificial intelligence for computer self-correcting of errors.

A dye is a substance applied to material, usually a
textile, for decorative purposes, to give it a colour different from that which it originally possessed.

A dyke (
dike) is a ditch or earthworks. The term is most often applied to earthworks built to reclaim land from the sea or rivers.

Dynamics is the branch of mechanics which consists of the study of the motion of matter and its causes.

Dynamite is an explosive consisting of nitroglycerine which has been absorbed into some inert material such as kieselguhr, sawdust or wood pulp. Dynamite was invented by Nobel in 1867.

A dynamometer is an apparatus for measuring power, or the rate of doing work.

Dyne is the unit of force. One dyne is that force which, acting on a
mass of one gramme, imparts to it an acceleration of one centimetre per second per second.

Dyspepsia (Indigestion) is a disturbance of the natural processes of
digestion, due sometimes to organic disease involving the alimentary canal, but usually to errors in diet or to nervous causes.

Dysprosium is a rare metal
element with the symbol Dy.

E Layer
The E Layer (Kennelly-Heaviside Layer) is a region of ionized gas in the ionos here, which reflects practically all incident medium frequency
radiation, absorbing very little.

An earnest is a small sum of money or token given to bind a bargain between two parties.

The earth is the third
planet from the sun.

Earth Metal
Earth Metals are the metals which in combination with oxygen form alkaline earths. They are calcium, strontium and barium and are never found in an uncombined condition, but oxidise rapidly into lime, strontia and baryta, the alkaline earths.

An easel is a stand or support for an artist's canvas.

Easement is a privilege without profit, i.e. a right attached to one piece of land which allows the owner of the land to use the land of another in a particular manner.

East India Company
East India Company was an incorporated company trading with India and the East Indies. East India Companies were founded in the 17th and 18th centuries by many European countries, the most important being the English East India Company with a close rival in the Dutch East India Company. The English company obtained from Queen Elizabeth I a charter in 1600 conferring the monopoly of trade with the East Indies.

Eaves are the edges of a roof projecting beyond the walls.

Ebonite is a hard product obtained by fully vulcanising
rubber with more than 20 percent of its weight of sulphur. Ebonite is very resistant to corrosion and as an excellent insulator was employed in the electrical industry.

Ebony is the heart-wood of various
species of Diospyros, trees of the order Ebenacea. It is a heavy, deep black wood used in piano keys and inlaying.

Ecarte is a card game for two players, first played in
Paris in the 19th century. A deck of 32 cards is used, all the cards below 7 being removed. The ace ranks between the 10 and the jack. Spectators are allowed to bet on the game.

An echinus is the rounded moulding in the capital of a Doric

Echo Sounding
Echo Sounding is measurement of the depth of the ocean by directing a sonic or ultrasonic pressure wave vertically downward and determining the time taken before the echo is received.

Eclampsia is the name given to the sudden convulsive seizures sometimes occuring in pregnant women as a result of
Bright's disease.

An eclipse is the passage of a celestial body through the
shadow of another.

Ecology is the study of the relationship between
plants and the places in which they grow. The term is becoming used to describe the opposition to man-made pollution and destruction of nature, hence an ecologist today is thought of more as an environmental campaigner than a botanist.

Ecstasy is an illegal drug synthesised 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 Environmental Protection Agency in the USA using FORTRAN.

Eddy Current
Eddy currents (Foucault currents) are electric currents induced in a conductor by a varying magnetic field, for instance, in the core of an inductor or transformer.

Effervescence is the rapid escape of gas from a liquid, usually due to chemical

Effort is strenuous exertion.

An egg is a body specially developed in the females of
animals which when impregnated by a male sperm develops into the young of the animal.

Eisteddfod is a Bardic
Congress held periodically in Wales for the encouragement and development of Welsh music and literature. Its origins date back to pre-Christian times, though the first recorded Eisteddfod was held in the 6th century.

Ejectment was a common law
action, abolished in 1852, to recover possession of land and damages for the wrongful withholding of it.

Electric current
Electric current is the movement of electric charge. In a
conductor the current consists of a drift of electrons towards the positive pole of the applied electric field. In an electrolyte or in a gas it consists of the migration of positive ions towards the negative electrode and of negative ions and/or electrons towards the positive electrode.

An electrode is a
conductor by which an electric current enters or leaves an electrolyte or an electron tube. The positive electrode is called the anode and the negative electrode is called the cathode.

Electrum is a naturally occurring
alloy of gold and silver. The gold content varies but is usually around 65 - 80 percent. Other metals, such as copper, bismuth or palladium are also sometimes present. In Ancient Greece the term electrum was given to an alloy of gold and silver containing 80 percent gold.

Elegit is a legal writ ordering the seizure of a debtor's land in order to satisfy a judgment debt.

Elegy is a form of poetry of a mournful and reflective character, particularly a mourning song for a departed

An element is a substance that cannot be split chemically into simpler substances.

see "

Elephantiasis is a disease characterized by inflammation of the fibrous connective
tissue, leading to excessive swelling of the leg, scrotum, arm or breast and more rarely other parts of the body. It is caused by the parasitic worm Filaria which blocks the lymph vessels, and at the same time causes irritation of the skin.

Eleusinian Mysteries
The Eleusinian Mysteries were
Greek initiation ceremonies connected with the worship of Demeter, believed to have been first performed at Eleusis.

Elgin marbles
Elgin marbles are a collection of ancient Greek sculptures assembled by the 7th earl of Elgin and brought to England in 1812

The ell was an
English unit of measurement equal to 45 inches.

Emanation is a theological doctrine which regards individuals as outpourings of the divine essence. It denies the personality of both God and man.

Emancipation Act
The Emancipation Act abolished slavery throughout the British colonies on
August 28th 1833. 20 million pounds was paid as compensation to slave-owners.

Embalming is the preparation of dead bodies so that they will not decay. The ancient Egyptians were especially expert and manny mummies are still preserved.

An embassy is an ambassador's residence.

Ember Days
Ember Days are the Wednsday,
Friday and Saturday following September 14th, December 13th, the first Sunday of Lent and Whitsunday, set apart in the Roman Catholic Church and the Church of England for prayer, especially for those about to be ordained.

In law, embezzlement is the theft by a clerk or servant of money or goods received by him on behalf of his employer. It differs from larceny in that the original receiving of the property was lawful.

Emblements is the right of an agricultural tenant, whose lease lapses before
harvest, to enter the land and gather crops.

Embolic gangrene
see "

Embossing is the art of producing a design on paper, cardboard, metal,
leather &c., by forcing or stamping out appropriate portions of the under-side to give a raised effect.

In law, embracery is the misdemeanour of attempting to influence a juryman to favour one side< otherwise than by evidence and argument given in open
court. A juryman allowing himself to be corrupted is equally guilty of embracery.

Embrasures are the spaces or openings between two merlons (
solid portions) of a battlement.

Embroidery is the art of ornamenting woven fabric into designs in needle-work. Embroidery differs from
tapestry in that the design is stitched on the top of a woven material, whereas in tapestry the design is woven into it.

An embryo is the offspring of an
animal before it has been born or emerged from its egg.

Embryology is the study of the development of embryos of
animals and plants, from egg-cells or ova. Since the ova of most organisms do not develope before fertilisation, the study of embryology begins with fertilisation, and follows the subsequent changes of the fertilised ovum, and the conditios influencing its development.

Emetine is an
alkaloid obtained from the dried roots of Psychotria ipecacuanha, a Brazilian plant. Emetine is a white powder employed in the treatment of amoebic dysentery and also as an anthelmintic.

Emigration is the departure from one's native country in order to take up permanent residence in another.

Eminent Domain
Domain is the right of the State to use private property for public purposes, particularly in war-time.

Emphysema is an
abnormal presence of air in certain parts of the body. Generally however the term is restricted to a peculiar affection of the lungs, exhibited in two forms, vesicular emphysema, dilation or rupture of the air-sacs, and interlobular emphysema, infiltration of air into the connective tissue beneath the pleura.

An Empire is a large
state or federation of states extending over a wide geographical area, and usually developed by the absorption of other peoples and countries. Empires are nearly always built up by the virile conquering and colonising expansion of a single State, but subsequently the individual provinces gradually attain independence.

Empire Day
Empire Day was an annual festival inaugurated in 1902 to celebrate on May 24th the achievement of the British Empire.

Empiricism is the theory that personal experience is the source of all
knowledge and that the mind was originally an absolute blank. The theory originated with Heraclitus and was characteristic of Greek speculative thought.

Employment Exchange
The British government established an office called the Employment Exchange in 1909 for the purpose of introducing unemployed men to vacancies notified by employers. In 1912 the office took on the additional role of administering unemployment insurance. Today, the office is known as the Department of Employment and the Employment Exchanges are called Job Centres.

Empyema is a pathological term describing a collection of
pus in a cavity, especially applied to pus in the pleural cavity of the lung.

An emulsion is an extremely fine dispersion of a liquid throughout another liquid with which it is immiscible. Industrial emulsions include margerine, and
paint. Within the natural world, the most common emulsion is blood.

Encephalitis Lethargica
Encephalitis Lethargica is a disease believed to be due to a
virus infection of the brain. The onset is sudden and takes the form of a chill. After a short period of recovery there is usually some disturbance of vision associated with palsy of the eye muscles. This is followed by muscular weakness and sudden mood swings followed by lethargy and possible death.

An encyclical is a circular letter on ecclesiastic affairs addressed by the
Pope to all the clergy and faithful of the Roman Catholic Church.

The word Encyclopaedia (Encyclopedia) was first defined in Sir
Thomas Elyot's Latin Dictionary (1538) as "that lernynge whiche comprehendeth all lyberall science and studies." It was first used as the title of a book by Johann Heinrich Alsted in 1608, by which time it had acquired its modern meaning of a book covering every branch of human knowledge. The term is also, however, applied to a work confined to some particular branch of knowledge. The distinction between an encyclopaedia and a dictionary is that the former explains subjects and the latter explains words.

Encyclopaedia Britannica
Encyclopaedia Britannica was first published as three volumes in 1771, and the second enlarged edition was published in 1778 and has been republished ever since to become one of the most famous encyclopaedias of all time.

Endosperm is the nutritive
tissue in plant seeds which feeds the growing embryo.

Endowment Insurance
Endowment Insurance is a form of insurance whereby, in return for regular contributions, a fixed sum is payable at death or at a certain age when the insured person ceases to pay premiums.

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 expels 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.

English is a term used to denote someone or something from

Engraving is the art of cutting a design on a hard substance, such as wood or metal.

Enjambement is the arranging of sentences and clauses in verse so that their ends do not coincide with the ends of the lines. It was introduced in order to give fluency and ease to verses.

An Enneastyle is a
Greek temple or other building having nine columns at the front.

An ensign is a flag or
banner used in the Army and Navy. The British naval ensign is red, white or blue, with a small Union Jack in the upper corner. The red ensign is flown by the Mercant fleet, the blue by the Royal Navy Reserve and the white, which includes a red St George's cross by the Royal Navy.

Entail is a system of land
tenure which was introduced by the statute De Donis in 1285, and by which the holder has only a life interest in the land, which passes on his death to his heirs.

Entente Cordiale
The Entente Cordiale was the semi-formal
alliance between England and France before the Great War. The alliance was first sought by France in 1903 seeking that in the event of a conflict with Germany, England would be at least neutral. In 1904 an agreement was signed whereby France had a free hand in Morocco and England a free hand in Egypt.

Enteric Fever
Enteric Fever is a term for typhoid fever and paratyphoid indicative of the
intestinal lesions met with in that disease.

Enteritis is a convenient term for disorders of the
bowel in which there is inflammation of the lining of the bowel wall. Varieties of enteritis include; dysentry, mucous colitis, typhoid fever and paratyphoid fever.

Enterokinase is a
hormone manufactured in the wall of the intestine and causes the pancreas to secrete when it is received.

Entomology is the branch of
zoology dealing with insects.

An entree is a complete dish consisting of meat, poultry or
fish with vegetable and a sauce. It is served before the "roast" course in a formal menu and may be either hot or cold.

Entrepot Trade
Trade is the trade in one centre in the goods of other countries.

An enzyme is a biological
catalyst that is not itself destroyed in the conversion process. Enzymes convert organic compounds into simpler substances and are formed by micro-organisms and cells.

The Eocene was the fourteenth geological period, 50,000,000 years ago.

Eocene System
Eocene System is the oldest of the four geological systems into which the Tertiary era is divided.

Eosin is the
potassium or sodium salt of tetrabromo-flourescein. It is a red substance which possesses brilliant flourescence in alkaline solution. It is used in acid solution as a red dye for wool and silk and is also used in red ink.

An epaulette is an ornamental fringed tab or badge worn on the shoulder as a distinguishing mark of rank. A
gold epaulette was worn by Britsh Naval officers in 1759 following the French adoption in 1759. Epaulettes were used on both army and navy uniforms during the 19th century, but were abandoned by the British Army in 1855.

Ephod was a term applied to some part of the dress of
Jewish high-priests, and used in the Old Testament where it appears to have several meaninings.

An epic is a poetical narrative of heroic achievments. It is largely dramatic in character, but embraces a greater area and admits many incidents, each of which might serve as a dramatic plot. In an epic the personality of the narrator is made much more obvious than is that of the author of a drama.

An epidemic is a disease which affects a large number of people in a particular locality at one time. As a
rule it is infectious, but may affect its victims independantly. Epidemics were frequent in the Middle Ages before sanitation and considered inevitable.

An epigram is a short witty or poignant poem used as an inscription on a tomb,
monument or altar.

An epigraph is an inscription carved on a
stone, statue or coin.

Epigraphy is the study of ancient inscriptions incised on some hard material, such as wood,
stone or metal, as distinct from palaeography which is the study of ancient manuscripts written on papyrus, parchment or a similar material.

Epilogue is a term usually applied in
English literature to a speech or short poem addressed to the spectators by one of the actors at the close of a play. It may also be the additional chapter of a book, after the tale proper has finished.

Episcopacy is a form of Church government whereby churches are grouped together in dioceses under the authority of a

Epistaxis is a technical term for bleeding from the

An epitaph is a short composition in verse or prose, nominally for the tomb of a deceased person and generally setting
forth his or her virtues and the survivors' regrets.

Epithany is a church festival held on January 6th. It was originally held to commemorate the baptism of Jesus, but now some churches celebrate it as the visit of the three
wise men to Jesus.

Epsom Salts
Epsom Salts is the popular name for hydrated magnesium sulphate, MgSO4.7H2O. It is used medicinally as a cathartic, and is also used for weighting textiles.

Erbium is a metal
element with the symbol Er.

Erg is the c.g.s. unit of work or
energy, equal to the work done when a force of one dyne acts through a distance of one centimetre.

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.

Ergosterol is a naturally occuring higher
alcohol which upon irradition with ultra-violet light changes into Vitamin D.

see "

Erratics are rocks transported by the
action of ice during the Quaternary Glacial Period, often for considerable distances. They help in determining the extent of the ice-sheets and the direction of their movement.

Erse is a variant of the word
Irish and is a designation given to the ancient Celtic languages of the Scottish Highlands and Ireland, but more usually confined to that of Ireland.

Erysipelas is a contagious disease due to the invasion of the
tissues by the streptococcus germ, producing fever and a local redness of the skin. The inflammation of the skin may spread to deeper tissues, producing widespread necrosis and other complications occuring such as pneumonia, nephritis or meningitis.

Erythrityl Tetranitrate
Erythrityl Tetranitrate is an anti-anginal drug used to reduce the
frequency and severity of angina attacks.

An escalator is a moving stairway used to transport passengers between two different levels, such as floors of a building or the
street and the platforms of an underground station. The first escalator was designed and patented by Seeburger and subsequently developed by the Otis Elevator Comapny in the USA and by Waygood-Otis Ltd in Britain. The escalator was first demonstrated to the public at the Paris Exhibition in 1900.

Eschatology is the study of the doctrines of the life hereafter and of the expected second coming of Jesus.

In feudal
tenure, escheat is a reversion of land to the lord, for want of a tenant qualified to perform the services.

An espalier is a wooden framework on which fruit-trees or creepers are trained.

Essay is a literary term which was originally applied to a draft or rough copy, and hence, by the modesty of the author, to an unpretentious but complete composition. It is now used to mean a prose composition of moderate length, limited to a single subject.

Essential Oil
The essential oils (ethereal oils, volatile oils) are a group of naturally occuring pleasant-smelling liquids of vegetable origin.

An estate is a portion of land in the possession of a single person or corporation.

Ester is an
organic compound formed by the reaction between alcohol and acid with the elimination of water.

In geography, an estuary is the broad mouth of a river which is affected by the tides, or more strictly, the region where sea and fresh
water meet.

see "

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.

Ethane is a
paraffin hydrocarbon.

Ethanoic acid
acid is an organic fatty acid.

Ethanol is the chemical name for

Ethene is an
alkene hydrocarbon gas.

Ether is an anaesthetic. It has the formulae (c2h5)2o.

Ethereal oil
see "
Essential Oil"

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 standardised as IEEE specification 802.3 .

Ethnology is the science dealing with the inter-relatedness of the
human family in terms of the physical appearance, customs, culture, art, economics etc.

Ethyl Acetate
Ethyl Acetate (acetic
ether) is a colourless liquid with a characteristic fruity odour prepared by the esterification of ethyl alcohol with acetic acid. It is used as a solvent and as a flavouring agent.

Ethyl fluid
Ethyl fluid is a mixture consisting principally of tetra-ethyl lead which was formerly added to
petrol as an anti-knocking agent.

Ethylene is a
gaseous hydrocarbon with the formulae C2H4. It contains one double bond and is the simplest example of an unsaturated compound.

Ethylene Glycol
Ethylene Glycol is a sweet syrupy liquid miscible with water and employed as an anti-freeze mixture in motor-car radiators and also as a solvent.

Etruscan Language
The Etruscan language was spoken by the people of ancient Eturia which corresponds to the modern

Etymology is the science of the origin and relationship of words.

Eucaine is a synthetic local anaesthetic with a chemical structure similar to that of

Euchre is a card game usually for 2, 3 or 4 players played with a piquest pack of 32 cards, omitting all below 7, and with an extra card or joker used which ranks as the highest trump.

A eudiometer is a chemical apparatus introduced by Priestley consisting of a graduated
glass tube with one end closed. By submerging the open end of the tube under water and introducing a known volume of gas, the change in volume that occurs in the reaction between the two gases can be measured. The eudiometer was first used in the estimation of the amount of oxygen in the air.

Eugenics is the science of selective breeding to control physical and mental characteristics.

The euphonium is a musical instrument of the
saxhorn family. The bass saxhorn in B flat used in brass and military bands.

Eurhythmics is a system of mental and physical culture invented by Jacques Dalcroze, based on the interpretation of music by means of rhythmical movements of the body and limbs. A carefully graded series of exercises aims at producing an intellectual appreciation of
rhythm, combined with perfect physical control, enabling the head and limbs to be moved independently of one another, and so to express several separate rhythms simultaneously.

see "

Europium is a rare metal
element with the symbol Eu.

Evipan is an anaesthetic which was discovered in the 1930s. It is the
sodium salt of N-methyl-cyclo-hexenyl-methyl-barbituric acid and was administered by intravenous injection providing surgical anaesthesia for around 20 minutes.

Excellency is a title of honour. It was first assumed by
Charlemagne in the 9th century. Today it is applied to all ambassadors.

The exchequer (or Treasury) is a government department dealing with
State finance. It was introduced by the Normans.

Exchequer Court
Exchequer Court was established during the reign of Henry I to deal with questions of finance. It later took upon itself judicial business. The equity business of the Exchequer was transferred to the Court of Chancery in 1842, and in 1873 became the Exchequer division of the High Court of Justice.

Excise is a tax on the production of goods.

An exequatur is a document issued by the Head of a
State, granting recognition to a foreign consul appointed thereto.

An extensometer is an apparatus employed for measuring the strain produced in material when stressed.

Extradition is the delivery of a person accused or convicted of a crime to the
State on whose territory the crime was committed, by the State on whose territory the criminal happens to be.