General Information (F-H)


F Layer
The F Layer is a region of the ionized gas in the
ionosphere, often known as the Appleton Layer. It is the most important layer from the point of view of long-distance radio communications.

FA Cup
The
Association Football Cup (FA Cup) competition was inaugurated in 1872, the final being played originally at Kennington Oval, it is now played at Wembley Stadium.

Fabliau
Fabliau is a form of early
French literature consisting of short versified tales, comic in spirit and intended primarily for recitation. They were mainly written between the 12th and 14th centuries in northern France, and caricature every subject, but paricularly women.

Fallow
Fallow is land left unsown for a period, usually a year. Fallowing is an ancient process, it has been known for centuries that the same crop frown on the same land deteriorates after a few years, partly because the
soil is exhausted and partly because of disease. By leaving the land for a year, it can recover and subsequent crops improve.

Fandango
The fandango is a Spanish
dance involving lively movements accompanied by the chatter of castanets, snapping of fingers, and stamping of feet.

Fantan
Fantan is a Chinese gambling game, in which bets are made on any corner of a rectangular card, with numbered corners. When bets have been made the banker places on the table a head of counters and divides them into fours. The winning number is decided by the number of counters in the last batch; if one counter is left over, number one wins, if 2 number 2 and so on. Fantan is a gambling card game for any number of players, played with a full deck of 52 cards.

Fantasia
In music, a fantasia is a more or less impromptu composition bound by no formal rules.

Farad
The farad is the unit of measurement of electrical capacitance. A
capacitor has a capacitance of one farad if a quantity of one coulomb has to be imparted to it in order to raise the pottential difference between the plates by one volt. More convenient units for small capacitances are the microfarad and the picofarad.

Faraday Cage
The Faraday cage is an earthed metallic wire or gauze screen enclosing electrical equipment to shield it from the influence of external electric fields.

Faraday Screen
A Faraday screen is an earthed wire screen placed in an equipment so as to prevent electrostatic but not electromagnetic coupling between components.

Faro
Faro is an old gambling card game, possibly of Italian origin.

Farthingale
A farthingale was a hoop made of whalebone or wood and used in its most extreme form in the 17th century as a support for widespreading skirts. The farthingale originated in
Spain and was the precursor of the crinoline.

Fasces
Fasces were bundles of wooden rods made of
elm or birch strapped together with an axe whose head protruded at right angles from the sticks. The fasces symbolised the authority of the senior magistrates of ancient Rome and were carried by the lictors who preceeded them.

Fascism
Fascism is a political movement which originated in
Italy, deriving its name from fasces, and which holds that the individual exists for the State, to whose good all his work and interests should be directed. Fascism originated in Milan in 1919, as a movement started by Benito Musolini.

Fathom
Fathom is a nautical measurement, being 2 metres.

Fatty acid
A fatty
acid is an organic hydrocarbon with a carboxyl group at one end.

Feast of Fools
The Feast of Fools was a mediaeval Christian celebration and merry-making.

Federal State
A Federal
State is a perpetual union of several sovereign States, which has organs of its own and is invested with powers over the member-States and their citizens. This direct power over the citizens of its member-States distinguishes a federate-State from a confederation.

Federation
A federation is a
union of States in which the participants retain autonomy in local matters, while a Central Government determines questions of common interest.

Feet
Feet is the plural of foot.

Fehling's Solution
Fehling's
Solution is a laboratory reagent consisting of a solution containing copper sulphate, caustic soda and a double tartrate of potassium and sodium (Rochelle salt). Fehling's solution is used in the laboratory as a method for the quantitative examination of sugars.

Felo-de-se
Felo-de-se is
latin for a felon with regard to himself, and is an old term describing someone who commits suicide. Until 1823 it was the practice in England to bury suicides at a cross-roads with a stake driven through the body, but a statute of that year directed burial in a churchyard or burial-ground, without religious service, between the hours of 9pm and midnight. In 1882 both these restrictions were removed.

Felt
Felt is a fabric which is not woven, but made of fibres, usually
wool, which when subjected to beating and vibration grip one another in the form of layers.

Felucca
A felucca is a fast
Mediterranean sailing vessel used chiefly for fishing. It is long and narrow, with a high bow and large lateen sails.

Fermentation
Fermentation is the breakdown of
sugars by bacteria and yeast.

Fermium
Fermium is a man made,
radioactive metal element with the symbol Fm. It is named after Enrico Fermi.

Ferret
A ferret is a domesticated
polecat.

Ferrite-rod Aerial
A ferrite-rod
aerial is a receiving aerial consisting of a small coil mounted on a short rod of magnetic ferrite. The coil is, in effect, a small frame aerial, and the function of the ferrite rod is to concentrate the magnetic flux from a large area surrounding the aerial. Like all frame aerials the ferrite-rod aerial has pronounced directional properties. Its main advantage however lies in its compact dimensions.

Ferrites
Ferrites are a class of chemical compounds having the general formulae MFe2O4, where M is a divalent metal. Certain of these compounds are
ferromagnetic, and possess in addition other properties which render them valuable for use in electric circuit components operating at high frequencies.

Ferrochrome
Ferrochrome is various alloys of
iron and chromium employed in the manufacture of steel.

Ferromagnetic
Ferromagnetic is a term applied to materials such as
iron, cobalt, nickel and certain alloys, which have a magnetic permeability very much greater than unity and which varies with the strength of the applied field.

Ferrous
Ferrous is a
chemistry term referring to materials which contain iron.

Fescennine Verses
The Fescennine Verses were ancient indigenous
Roman songs, composed extempore, and recited at rustic merry-makings, particularly weddings. They were generally playfully abusive or licentious.

Fibre Optics
Fibre Optics is a technology using
light as a digital information bearer. Fibre optic cables ( light guides ) are a direct replacement for conventional wire, coaxial cable and many forms of radio, including microwave. Fibre 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.

Fibroin
Fibroin (Fibrosin) is an albuminoid
protein which forms over 50 per cent of silk.

Fife
A fife is a small
flute originating from Switzerland and used in military bands.

Filariasis
Filariasis is a disease caused by a parasite of the family Filariidea which causes malnutrition and inflammation of the lymphatic vessels.

Filbert
The filbert is a
nut of the cultivated variety of hazel.

Filigree
Filigree is fine ornamental work of
gold or silver wire, closely interlaced.

Fillet
A fillet was a band worn as a headdress in ancient times. In architecture, a fillet is a band or listel used as a separation for mouldings.

Fin
Fins are expansions of the
skin or body wall, or the equivalent of limbs, by means of which aqautic animals preserve their balance and swim.

Fire
Fire is the rapid liberation of heat by the chemical combination of various substances with the
oxygen of the air, a process known as combustion.

Firedamp
Firedamp is the name given by miners to the explosive mixture of the
hydrocarbon methane with air, which sometimes occurs in coal-mines.

Fish Kettle
A
fish kettle is a large oval-shaped saucepan, usually fitted with a perforated tray with handles, and used for cooking fish.

Fives
Fives is a
ball game for 2 or 4 players, in which a small hard ball is struck with the hand against the walls of an enclosed court.

Fjord
A fjord is a long, narrow
inlet resulting from the subsidence of a mountainous coast and the subsequent flooding of the valleys.

Flageolet
The flageolet is an old musical wind instrument, the ancestor of the modern
tin whistle.

Flail
A flail is two pieces of wood joined by a
leather thong or short metal chain and used for threshing. One piece of wood is held and the other then swung.

Flat-foot
Flat-foot is a deformity of the foot in which the arch sinks so that the whole extent of the
sole is in contact with the ground.

Fleet Prison
Fleet Prison was a famous London Prison which stood in Farringdon Street, on what was called Fleet Market, from the River Fleet which flowed into the Thames. Its keeper was called the Warden of the Fleet. As far back as the 12th century the Fleet served as a Royal Prison. In the reigns of Mary and Elizabeth I it was used for religious martyrs and the political victims of the Star Chambers. In 1641 it became a place of confinement for debtors and persons commited for contempt of court, and rapidly acquired a notoriety for every kind of brutality and extortion. It was destroyed and rebuilt several times before being finally abolished in 1842.

Fleur-de-Lys
The fleur-de-Lys (
flower of lily) is an heraldic representation of an iris or garden lily. It was the armorial bearing of the Kings of France from 1147 and was also borne by some English families.

Flotsam
Flotsam are goods floating upon the sea, which belong to the
Crown unless claimed within a year and a day.

Flower
The flower of a higher
plant consists of one or two whorls of enveloping leaves surrounding the stamen and carpels, which are the organs essential for sexual reproduction.

Flugelhorn
The flugelhorn is a
brass musical instrument.

Fluorescein
Fluorescein is an
organic compound obtained by heating together pthalic anhydride and resorcinol. It is a red powder insoluble in water, but it dissolves in alcohol and also in alkalis, giving a brilliant green flourescence. It is used as a dye.

Fluorescence
Fluorescence is the process of emission of electromagnetic
radiation resulting from the absorption of certain types of energy.

Fluoride
Fluoride is the salt of hydrofluoric
acid.

Fluorine
Fluorine is a
gaseous element with the symbol F belonging to the group known as halogens. It is the most chemically reactive element (many substances ignite spontaneously in it), and for this reason it is never found uncombined.

Fluorocarbon
A fluorocarbon is a
compound in which hydrogen atoms of a hydrocarbon have been replaced with fluorine.

Fly-wheel
A fly-wheel is a heavy wheel whose inertia maintains a nearly uniform speed of rotation under variable load or driving force. The revolving fly-wheel is a resevoir of
energy by virtue of its movement of inertia, and its effectiveness depends on the amount of energy which it absorbs or gives up for a given change of speed.

Foal
A foal is a young
horse.

Fodder
Fodder is all manner of foods given to horses,
cattle, and other animals. It includes grass or any plant eaten green, or the same dried for convenience or for use in winter, and grain, beans, peas etc. or artificial products made from any nutritional material.

Fog
Fog is a
cloud that collects at the surface of the earth without any definite shape.

Fohn
In geography, a fohn is a hot, dry, local
Alpine wind produced by the desiccation of an air current in passing over the mountain ranges and its subsequent heating by compression on being drawn into the denser valley atmosphere.

Foil
In metallurgy, foil is a term for a thin sheet of metal intermediate between a leaf, such as
gold leaf, and sheet metal. It varies in thickness according to the constituent metal or metals. Very thin tin foil is used for backing mirrors, and in chemistry and electronics.

Folded dipole
A folded dipole is a dipole
aerial consisting of two conductors in parallel, only one of which is broken at the centre for connection to the feeder. This construction increases the bandwidth and the centre impedance of the aerial.

Folic acid
Folic
acid is a b vitamin, a lack of folic acid causes anaemia.

Folio
Folio is a sheet of paper folded once to make two leaves of a book or manuscript, and hence the term is given to paper of a large size used for this purpose.

Fondant
Fondant is a soft sweet made of flavoured
sugar.

Font
A font is a vessel, generally of
stone, used in the Christian Church for holding the water for the sacrament of Holy Baptism.

Food Council
The Food
Council was a body formed in 1925 on the advice of a Royal Commission to investigate charges of food profiteering and to take action in such cases. It had few powers, and the natural fall in prices soon made it unnecessary, however the Food Council did sponsor the Weights and Measures Act of 1926.

Foolscap
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.

Foot
The foot is a unit of the imperial scale of measurement of length equivalent to 12 inches or 30.48 centimetres.

Foot-and-Mouth Disease
Foot-and-Mouth Disease is a desease of horned
cattle, sheep, etc. caused by a virus and characterised by the appearance of vesicles on the mouth, tongue and elsewhere, and salivation and champing of the mouth. The disease is intensely sontagious, and has an incubation period of between 2 and 5 days.

Football
Football is the name of several games involving the kicking of an inflated
ball around a pitch, the modern football games evolving around the middle of the 19th century.

Forecastle
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.

Forelock
A forelock is a wedge put through a hole in a bolt to keep the bolt in place.

Foresheets
The foresheets is the inner part of the bows of an open
boat where the bowman stands.

Forest
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 privileged for game generally belonging to the sovereign and set aside for his recreation.

Forge
A forge is a blacksmith's fireplace or furnace for melting and refining metal.

Formaldehyde
Formaldehyde (methyl
aldehyde) is the simplest representative of the aldehydes. It has the formula H.CHO, and is a colourless and very pungent gas. It is very soluble in water. It has a powerful preserving effect and is used in aqueous solution for preserving anatomical specimens.

Formalin
Formalin is an
aqueous solution of formaldehyde (40 per cent) and often 15 per cent methyl alcohol. It is used as a disinfectant and as a preservative.

Formic Acid
Formic
acid is the lowest member of the fatty acids. It has the formula H.COOH and is found in nature in ants, stinging nettles, and in various parts of the animal body. Commercially it is used in tanning and electro-plating.

Fortissimo
Fortissimo is a musical term directing the singers to sing with the utmost strength and loudness.

Foucault Current
see "
Eddy Current"

Foundling Hospital
Foundling hospitals were charitable institutions for the care of children abandoned by their parents. They were first founded to reduce instances of infanticide during the 7th and 8th centuries by church authorities and their numbers increased rapidly during the Middle Ages, especially in
France.

Fountain-pen
A fountain-pen is a refillable pen which carries its own supply of ink which runs to the writing point as required from a reservoir in the holder.

Fowler's Solution
Fowler's Solution is a solution of potassium arsenite, prepared by boiling together arsenic trioxide and potassium bicarbonate in water. It was used in medicine as a mild tonic for digestive disorders.

Fox-trot
The fox-trot is a ball-room
dance danced against jazz music.

Frail
A frail is a rush
basket for packing figs and raisins.

Fram
The Fram was a three-masted schooner built in 1892 for
Nansen's expedition to the Arctic, and used by Amundsen in the Antarctic in 1911.

Franckincense
Franckincense is a gum
resin obtained from trees of the genus Boswellia, used in the making of incense and in ancient times in medicine.

Frangulin
Frangulin is a yellow crystallizable
dye extracted from the bark of the alder. It is used to dye wool, silk and cotton.

Frankincense
Frankincense is an incense derived from the
resin of the tree boswellia.

Franking
Originally, franking was the right of sending letters free of charge. It was claimed for letters both sent and received by the
House of Commons in 1660, and fully legalised in 1764 when all members of both Houses were allowed to send 10 and receive 15 letters a day gratis. The priviledge was withdrawn on the introduction of the penny postage in 1840. Today the term is most commonly applied to the mechanical stamping of letters and parcels in place of fixing an adhesive stamp.

Franklin Aerial
The
Franklin aerial is a directional aerial consisting of a number of radiating elements, uniformly spaced on a line at right angles to the desired direction of maximum radiation.

Free Lance
The term Free
Lance was originally a soldier who fought as a mercenary for anyone who would pay him for his service. Now the term is applied to anyone who works for anyone who will pay them, but is not on the regular staff of any company, such as a writer for example.

Free Libraries
Free Libraries are libraries supported by municipalities, counties or charitable organisations etc. available to the public without charge. The first was established in
Manchester in 1653.

Freebench
Freebench was an
English right of a woman during her widowhood to an interest, generally one-third, in her late husband's copyhold land. It was abolished in 1925.

Freemasonry
Freemasonry is a cult with a secret ritual, considered by some to have originated with
Solomon and the building of the Temple, but in its modern form dating from the mid 18th century when the Grand Lodges of England, Scotland and Ireland were constituted. Members are mainly well-to-do businessmen.

French
French is a term used to denote someone or something from
France.

French Chalk
French Chalk is a form of steatite or talc, used by tailors for marking cloth for which its softness and burability on the material make it very suitable. It is also used as a dusting agent to prevent adhesion of a tacky surface, as a filler in plastics and to polish floors. It can be distinguished from ordinary chalk by its greasy feel.

French Revolution
The
French Revolution occured in 1789 and overthrew the despotic Bourbon Monarchy, only to itself be overthrown by the Empire of Napoleon. In 1830 another revolution overthrew the again reigning monarchy, and again in 1848.

Frequency Drift
Frequency drift is a phenomenon which affects electronic circuits. It is variations in the natural frequency of an oscillatory
circuit of an oscillator due for example, to changes of capacitance with changes of temperature.

Frequency Modulation
Frequency
modulation is a system of radio transmission in which the amplitude of the carrier remains constant but the frequency is varied in accordance with the amplitude of the modulating waveform. In frequency modulation the loudness of the applied audio-frequency modulation is represented by the amount of change of carrier frequency, and the frequency of the signal is reprented by the number of times the carrier frequency is changed every second.

Fresco
A fresco is a painting done on plaster.

Fret
In architecture, a fret is a decorative pattern consisting of a continuous series of short, straight lines or bars joining one another or interlacing, usually at right angles.

Fricasse
Fricasse is a dish consisting of small pieces of white meat in a flavoured white sauce made from the
stock in which the meat was cooked, with the addition of milk.

Friday
Friday is the fifth
day of the week, the name derives from the Saxon Frige-doeg, the day sacred to Freya.

Frith Gild
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
Fructose (fruit-sugar or laevulose) is a simple and very sweet
sugar found in plant juices, fruit and honey. It is a mono-saccharose, white, crystalline compound.

Fruit
Fruit is a botanical term for the mature
ovary of a plant comprised of two parts, the pericarp and the seed.

Fruit-sugar
see "
Fructose"

Fuchsine
see "
Magenta"

Full Duplex
Full Duplex is a communications term referring to a
circuit which allows independent transmission information in both directions simultaneously. - Synonym: In wire telephony, 4 wire circuit.

Fulminate
Fulminates are the mettalic salts of fulminic
acid. They can be made by dissolving a metal in strong nitric acid and adding alcohol. The fulminate is then precipitated. Fulminates are highly explosive compounds used for the manufacture of detonators.

Funicular Railway
A funicular railway is a railway for transporting passengers up a steep incline. They often run on the principle of balance, two carriages of equal weight being joined by a long
cable which passes over a pulley at the upper end. Small power is required at the pulley to bring one car up the slope while the other descends.

Furlong
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 furlong derives from furrow-length.

Furlongs
see "
furlong"

Fuse
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.

Fusel Oil
Fusel oil is the residue left after removing the ethyl alcohol from various liquors obtained by
fermentation, potato spirit being the best source. Fusel oil consists principally of isoamyl and normal amyl alcohols, together with smaller amounts of butyl alcohol, and various aldehydes and esters. It is a poisonous, unpleasant smelling, oily liquid principally used as a source of amyl alcohol.

Gabardine
Gabardine is a fabric particularly suited to water-proofing, composed of fine
botany wool yarn warp, and cotton weft. The name is also given to a raincoat made from the material.

Gabelle
Gabelle was a tax on salt imposed in
France from 1286 until 1790. It was levied unequally and caused a lot of discontent.

Gabilla
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.

Gadolinium
Gadolinium is a metal
element with the symbol Gd of the group of rare earth metals. It is found in the mineral gadolinite.

Gaff
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
Galactose (lactoglucose) is a
sugar formed together with glucose when lactose is boiled in dilute acids. It occurs naturally in ivy.

Galalith
Galalith (erinoid) is a synthetic
plastic material manufactured by the interaction of casein and formaldehyde. It is odourless, insoluble in water, and only with difficulty inflammable.

Galantine
Galantine is a dish which consists usually of a white meat, well flavoured and made into a roll. It is served cold and has a glazed surface.

Galaxy
A galaxy is a congregation of
stars held together by gravity.

Gall
A gall is a
growth caused on plants of various kinds by parasitic mites (Phytoptidae).

Galley-slave
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 until 1748.

Gallic Acid
Gallic
Acid (Trihydroxy-benzoic Acid) 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.

Galliot
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.

Gallium
Gallium is a rare metal
element with the symbol Ga.

Gallon
The gallon is a unit of capacity measurement equivalent to 4 quarts or 4.546 litres, 8 pints.

Galvanometer
A galvanometer is an instrument for measuring an electric current by the deflection 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.

Gamboge
Gamboge is a gum-resin obtained from a
tree growing in the Far East. It is used as a paint-pigment, in the manufacture of varnish, in tanning and as a purgative.

Gamete
Gametes are cells taking part in sexual
reproduction. The female gamete is the ovum (egg-cell) and the male gamete of animals is the spermatozoon, and the male gamete of plants the spermatozoid.

Gamma Rays
Gamma Rays are a short, intense burst of electromagnetic
radiation emitted by an unstable nucleus of radioactive material. Gamma rays have no electrical charge and can penetrate even thick lead and concrete.

Gangrene
Gangrene (Mortification) is a term applied in medicine to the death of a considerable bulk of body
tissue. Gangrenes are classified according to their cause. Embolic gangrene is due to the blocking of an artery, which prevents blood reaching the part. Senile gangrene is due to malnutrition of the part in very old people. Traumatic gangrene is due to injury. Hospital gangrene, gas gangrene and others are due to infection by organisms. The gangrene may be either dry or moist. In dry gangrene the part is hard, shrunken and black. In moist gangrene it is swollen and putrescent.

Ganja
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
Gas is a form of matter where the molecules move randomly.

Gas gangrene
see "
Gangrene"

Gas Oil
Gas
Oil is a liquid petroleum distillate with a viscosity somewhat below that of lubricating oils. It is used in the manufacture of coal gas and as the charging stock in cracking plants where it is broken down for use as motor spirit.

Gaseous
see "
gas"

Gastritis
Gastritis is inflammation of the
mucous membrane lining the stomach.

Gauge
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
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 centimetre. 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).

Gavotte
The gavotte was a stately and ceremonious
dance, like the minuet, which developed into a stage dance too elaborate for performance in the ball-room.

Geiger-Muller Tube
The Geiger-Muller Tube is an electron tube forming an ionization chamber and used as a
radiation counter or meter.

Geissler Tube
The Geissler Tube is a discharge tube, often of ornamental shape, and exhausted to a pressure of a few millimeters of
mercury. They are used for demonstrating the luminous effects accompanying electric discharges through rarefied gases.

Gelatine
Gelatine (glutin) is a
compound of animal origin obtained by the hydrolysis of an albuminoid protein, collagen, found in the bones, catrilages and connective tissues. It is used in the manufacture of soups, jellies and pharmaceutical capsules for drugs.

Gemini
Gemini is a
sign of the zodiac.

Genus
In scientific classification, a genus is an assemblage of
species possessing certain characteristics in common by which they are distinguished from others.

Geode
A geode is a round hollow nodule containing earthy matters, sometimes
quartz, sometimes agate. Geodes are found in most volcanic rocks and are formed by water depositing materials in the hollows of these rocks.

Geophagism
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
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.

Geotropic
Geotropic is a biological term describing
plants whose roots grow downwards into the soil in response to gravity.

Geotropism
In
botany, the term geotropism refers to a disposition or tendency to turn towards the earth.

Geranial
Geranial (citral) is a pleasant-smelling
aldehyde which occurs in various essential oils. It can be obtained from lemon-grass oil and is used in the manufacture of perfumes.

German
German is a term used to denote someone or something from
Germany.

German Silver
see "
Nickel Silver"

Germanium
Germanium is a metal
element with the symbol Ge used in the manufacture of electronic semiconductors. It has low conductivity at room temperature, but increasing conductivity with increases of temperature.

Germination
Germination is the sprouting of seeds into
plants. It takes place after the seeds have been shed, when ripening changes continue.

Gestation
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).

Geyser
In geography, a geyser is a volcanic boiling
spring. They are common in Iceland and New Zealand.

Ghee
Ghee is the clarified butter-fat obtained from
buffalo butter. It is widely used in India for cooking.

Ghetto
A ghetto was a part of a city in which
Jews were compelled to live, shut off from the rest of the city and forced to pay a tax for the dubious privilege of living there.

Gibus
The gibus is a type of
opera hat named after its maker.

Gill
The gill was an
English unit of liquid measurement equivalent to 0.25 pints.

Gimbal
Gimbals (Cardan Suspension) are devices used chiefly on board
ship for suspending objects so that they remain vertical in spite of any inclination of the support to which they are attached.

Gimp
Gimp was a thick, silk-covered cord used to line crinoline dresses. The term also describes a part of a nun's head-gear.

Gin
Gin is an
alcoholic beverage flavoured with juniper.

Ginal
Ginal is a Jamaican term for a person who misleads other people in order to gain tangible benefit. For example, a woman who deceives a man into supporting her or providing her with goods by telling him that she likes him when she really has no interest other than in material gain.

Glacier
In geography, a glacier is a
massive crystalline block of ice or snow. They are found in regions of perpetual snow.

Glanders
Glanders is a disease attacking horses, due to a bacillus (Bacillus mallei), which affects the
lungs and sometimes the membrane of the nose and throat. The disease may be passed to man by contagion.

Glass
Glass is a brittle substance made by fusing
silica, an alkali and a base.

Glucic Acid
Glucic
Acid is an acid produced by the action of alkalis on glucose or of acids on cane-sugar.

Glucose
Glucose is a simple form of
sugar with the formulae c6h12o6.

Glucoside
The glucosides are a group of
carbon compounds occurring in plants, and characterised by the fact that on hydrolysis or saponification with dilute acids a sugar, usually glucose, is formed along with other products.

Gluten
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.

Glutin
see "
Gelatine"

Glycerol tri-stearate
see "
Stearin"

Glycine
Glycine is a simple
amino acid.

Glycogen
Glycogen is a
polysaccharide retained in the liver as a carbohydrate store.

Goldschmidt Alternator
A Goldschmidt Alternator is a dynamo-electric
ac generator for producing currents of high frequency. A number of windings arranged alternatively on the rotor and the stator are tuned to successively high frequencies. Currents of one frequency in one of the coils, say on the rotor, produce currents of higher frequency in one of the stator coils, and these in turn produce currents of still higher frequencies in the next rotor coil. The process continues for the complete series of coils, and frequencies up to some 100 khz can be produced.

Goldschmidt Process
see "
Thermite Process"

Golf
Golf is an outdoor game in which a small
ball is struck with a club.

Gonidia
Gonidia are the secondary,
green, spherical cells in the thallus of lichens which distinguish lichens from fungi.

Gonorrhoea
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.

Gorget
A gorget was a piece of body
armour for the protection of the throat.

Gout
Gout is a disease marked by an excess of uric
acid in the tissues.

Grain
The grain is a unit of measurement of the
avoirdupois scale equivalent to 0.0648 grams.

Grains
see "
grain"

Gram
Gram is the metric unit of
mass; one-thousandth of a kilogram.

Gravel
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
Gravity is the force of attraction between two objects resulting from their
mass.

Greaves
Greaves was body
armour worn at the front of the lower part of the legs and buckled behind the leg.

Greeks
see "
Greek"

Guitar
A guitar is a stringed musical instrument played with the fingers or a plectrum.

Gules
Gules is the heraldic name for the colour
red. It ranks highest among the colours.

Gulf-stream
The Gulf-stream is the warm north-east drift current of the north
Atlantic originating from the equatorial drift.

Gum Arabic
Gum Arabic is obtained from the
acacia.

Gymnosperm
A gymnosperm is a
plant with a naked seed, there being no proper ovary the seeds being fertilised by the pollen coming into direct contact with the foramen of the ovule without the intervention of a stigma.

H Aerial
An H
aerial is an aerial array comprising a dipole and one reflector.

Hackney Carriage
see "
Hackney Coach"

Hackney Coach
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.

Haemorrhoids
see "
Varicose Veins"

Hafnium
Hafnium is a metal
element with the symbol Hf occurring in zircon and used in nuclear reactors.

Hajj
Hajj is the
Muslim pilgrimage to Mecca.

Half-hitch
The half-hitch is a type of
knot.

Hall Effect
The
Hall effect is when a piece of semiconductor material with a cuurent flowing through it is subjected to a magnetic field a voltage is set up between the faces of the material which are perpendicular to both the current and the field. It is caused by the charge carriers present in the semiconductor being deflected in the magnetic field.

Hallmark
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 authorised 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
Halogen is a particular group of
elements with similar bonding properties.

HAM-RPM
HAM-RPM is a knowledge-based conversationalist that reasons with fuzzy information. It was developed at the University of
Hamburg.

Hand
The hand was an
English unit of measurement applied to horses. One hand being four inches.

Harmaline
see "
Magenta"

Hartley Oscillator
A
Hartley oscillator is athermionic oscillator comprising a triode with an oscillatory circuit connected between anode and grid, and inductive coupling bwteen the anode and grid circuits, via a tapping on the inductive element of the tuned circuit.

Hashish
Hashish is the
resinous form of cannabis.

Heat-stroke
see "
Sunstroke"

Hectare
The hectare is the metric unit of area equal to 10,000 square meters (2.47 acres),
symbol ha.

Helical Aerial
A helical
aerial is an aerial array composed of a conductor wound in the form of a helix, the circumferance of each turn being equal to a whole number of wavelengths.

Heliotropic
Heliotropic is a biological term for
plants which turn their stems so as to expose as much leaf surface to the sunlight as possible.

Helium
Helium is a
gaseous element with the symbol He.

Helix
A helix is a circular
spiral with all the turns the same diameter.

Helmet
A helmet is an item of clothing designed to protect the head.

Hennin
The hennin was a cornet head-dress in the form of an elongated cone hung with elaborately arranged veils and worn by women in 15th century
England.

Henry
Henry is the unit of
inductance. An inductor has an inductance of one henry if an electro-motive force of one volt is induced when the current changes at the rate of one ampere per second.

Hepatitis
Hepatitis is an inflammatory disease of the
liver.

Hepatoscopy
Hepatoscopy is divination by
reading the marks on the liver of a slaughtered animal.

Heptathlon
The heptathlon is a 7 event
athletics discipline.

Heptode
A heptode is a high-vacuum thermionic
valve having seven electrodes, namely an anode, a cathode and five grids.

Heraldry
Heraldry is the subject of armorial bearings.

Herb
A herb is a
plant whose aerial parts do not remain above ground following the growing season.

Heroin
Heroin is a powerful opiate
analgesic.

Heterodyne
Heterodyne is the process whereby two oscillations of different frequencies are combined to produce other oscillations, and particularly oscillations having a frequency equal to the difference between the frequencies of the two original oscillations.

Heuristic Dendral
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
Hieroglyphics are signs comprising the picture writing of the ancient Egyptians.

High Tension
High Tension is a comparative term used in electronics to denote high voltages.

Himation
An himation was a woollen
cloak worn by the ancient Greeks.

Hinterland
Hinterland is a country lying immediately behind a
coast, river or frontier.

Hockey
Hockey is a game played with hooked sticks and a
ball.

Hodometer
A hodometer was an early device for measuring the distance travelled by a vehicle.

Hoe
A hoe is an instrument for cutting up weeds and loosening the
earth in fields and gardens.

Honey
Honey is a sweet syrup made by bees from
nectar.

Horsepower
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.

Hospital
A hospital is an institution for caring for the sick and injured. The name derives from
House of God's Hospitality, and were founded by the church in obedience to the injunction to care for the sick. Not until the late Victorian era would doctors attend to sexually transmitted diseases, believing them to be punishments from God. A view still held by many religious people today, although now more commonly applied to "AIDS" than other STDs.

Hospital gangrene
see "
Gangrene"

House
A house is a building for
human habitation.

House of Tudor
The
House of Tudor was an English dynasty descended on the male side from Owen Tudor, a Welsh knight who married Catherine, widow of Henry V, and was the grandfather of Henry VII; and on the female side from Edward III through the Beauforts and John of Gaunt. The Tudor monarchs were Henry VII, Henry VII, Edward VI, Mary, and Elizabeth I.

Hoy
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.

Huff
In the game of
draughts, if a player in a position to capture an opposing piece neglects to do so, his opponent may "huff" (remove from the board) the piece which should have made the capture, if he so wishes to do so.

Humus
Humus is partly decomposed
organic matter. Found in soil.

Hundredweight
The hundredweight (cwt) is a unit of measurement of the
avoirdupois scale equivalent to 4 quarters, 112 pounds or 50.8 kilograms.

Hydralazine Hydrochloride
Hydralazine hydrochloride is a drug used to reduce high
blood
pressure and to aid in relieving congestive heart failure. It has the
possible side effects of: headaches, dizziness on changing position
quickly, increased heart rate, angina, palpitations, nausea, vomiting,
diarrhea, decreased appetite, rash and weight gain.

Hydrocarbon
A hydrocarbon is a chemical containing only
hydrogen and carbon.

Hydrocarbons
see "
hydrocarbon"

Hydrochlorothiazide
Hydrochlorothiazide is an antihypertensive and
diuretic drug used to
controls, but not cure high, high blood pressure and reduce fluid retention (edema).
It works by forcing sodium and water excretion, thereby reducing the body fluid.

Hydrocyanic Acid
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.

Hydrogen
Hydrogen is a
gaseous element with the symbol H.

Hydroxide
A hydroxide is an inorganic
compound containing one or more hydroxyl groups.

Hydroxy-toluene
see "
Cresol"

Hypo
see "
Sodium thiosulphate"