Aba
An aba is a sack like garment worn by Arabs.
Abac
An abac is a two dimensional matrix, or table, found at the back of a road atlas which shows the distances between major towns etc.
Abacus
An abacus is a counting frame with balls sliding on wires. It was first used before the adoption of the ten digit numeric system and is still widely used in China.
Abaft
Abaft means towards the rear of a ship.
Abbey
An abbey is a body of monks or a monastic building.
Abbreviate
Abbreviation
ABC Process
Abdicate
Abdomen
Abduct
Aberdeen Act
Aberration
Abiogenesis
Ablution
Abnormal
Abode
Abomasum
Abort
Abortion
Aboulia
Abracadabra
Abrasion
Abridge
Abscess
Abseil
Absentee Tax
Absinth
Absolute Temperature
Absorber Circuit
Absorptiometer
Abstract
Acardia
Accelerating Electrode
Accelerating Grid
Acceleration
Accelerator
Accelerator Valve
Accelerometer
Accent
Accolade
Accomplice
Accordion
Accounts
Accumulator
Ace
Acetal
Acetaminophen
Acetic acid
Acetic ether
Acetone
Acetylene
Achor
Achromatic Telescope
Acid
ACK
Aclinic
Acne
Aconitine
Acorn Valve
Acoustic
Acoustic Feedback
Acre
Acridine
Acriflavine
Acromegaly
Acronym
Acrophobia
Acropolis
Acrostic
Acrylic
Act of Succession
Actinide
Actinium
Actinometer
Acts of Supremacy
Adaptive Equalisation
Adcock Aerial
Addiscombe College
Addison's Disease
Adhesive
Adipocere
Adit
Admiralty
Adobe
Adult
Adytum
Adze
Aelfric Society
Aeolopile
Aeon
Aerated Water
Aerial
Aerodrome
Aerophore
Afrikaans
Agar
Agenda
Aggry Beads
Agoraphobia
Agricultural Children Act
Agricultural Hall
Air
Aircraft
Aisle
Albugo
Alchemy
Alcohol
Aldehyde
Ale
Aleurometer
Algebra
ALGOL
Algorithm
Alkali
Alkaloid
Alkane
Alkene
Alkyl
Allergy
Alley
Allies
Alloy
Alluvium
Alpha
Alpha Particles
Alpha Rays
Alpha-tocopherol
Alphabet
Altar
Alternating Current
Althing
Altimeter
Altitude
Aluminium
Alundum
Amazon
Ambaree
Amber
Ambergris
Ambidextrous
Amenorrhoea
American
Americium
Amice
Amine
Amino acid
Ammeter
Ammonia
Ammonium
Ammonium Chloride
Amoxicillin Trihydrate
Ampere
Amphetamine
Amphitheatre
Ampicillin Trihydrate
Amplifier
Amplitude
Amplitude Modulation
Amyl
Amylene
Amylum
Anabaptist
Anaemia
Analgesic
Analogue Computer
Anatomical Alloy
Anchor
Andante
Anemometer
Angiosperm
Angst
Angstrom Unit
Aniline
Anion
Anker
Annuity Tax
Anode
Anorthoscope
Anosmia
ANSI
Anthrax
Anthropology
Antiarin
Antibiotic
Antidote
Antimony
Antipyrine
Antiseptic
Anvil
Anxiolytic
Apartheid
Aperture
Aphasia
Aphelion
Apogee
Apollo Asteroid
Apollo Project
Apostle Spoons
Applique
Aqua
Aquatint
Aqueduct
Aqueous
Archeozoic
Archipelago
Arcnet
Areometer
Arete
Argon
Aries
Armature
Armour
Arms
Army
Arroba
Arsenal
Arshin
ASCII
Ash Wednesday
Asphalt
Aspirin
Assay
Assize of Battle
Association Football
Astatine
Astern
Asteroid
Asthma
Astrology
Astronomy
Asynchronous
Athletics
Atmolysis
Atmosphere
Atoll
Atom
Atrium
Atropine
Attenuation
Attenuator
Audiphone
August
Avenin
Avoirdupois
Axe
Azoimide
Abbreviate means make shorter.
An abbreviation is a short form of a word or words.
The ABC Process was a method of purifying sewage which derived its name from the articles used: sulphate of alumina, blood, charcoal and clay.
Abdicate means to renounce one's thrown.
The abdomen is the part of a creature's body between diaphragm and pelvis.
Abduct means to take away by force or fraud.
The Aberdeen Act was introduced by the earl of Aberdeen, and passed in 1845, to enforce the observance of a convention made with Brazil in 1826 to put down the slave trade. It was repealed in 1869.
Aberration is another word for error.
Abiogenesis is a term applied by professor Huxley in 1870 to the theory that living matter may be produced from non-living.
Ablution is ceremonial washing.
Abnormal means deviating from normal.
Abode is a place where something lives.
An abomasum is the fourth stomach of a ruminant.
Abort means to terminate early.
Abortion is the expulsion of the foetus from the uterus.
In psychology aboulia is the loss of will.
Abracadabra is a qabbalistic magic word.
An abrasion is a sore place on the skin caused by rubbing.
Abridge means to shorten by condensing.
An abscess is a pus filled infection of an animal.
In mountaineering abseil means to descend using a rope.
Absentee Tax was a tax of 4 shillings in the pound levied in Ireland in 1715 on the incomes and pensions of absentees. It was long complained of and was abolished in 1753. A tax of 2 shillings in the pound was proposed in 1773 by Flood and in 1783 by Molyneux, but neither attempt to reinstate the tax were successful.
Absinth is a strong alcoholic drink containing from 60 to 80 percent alcohol. It contains wormwood oil which gives it its distinctive taste, but also toxic qualities.
Absolute Temperature is temperature based on the absolute zero of temperature (-273 degrees Celsius or o degrees Kelvin) at which a body possesses no thermal energy.
In electronics, an absorber circuit is a combination of a resistor and a capacitor in series, connected across the terminals of a switch or other circuit-breaking device in an oscillatory circuit. Its function is to damp the circuit and thus to prevent sparking or arcing when the current is interrupted.
An absorptiometer is an instrument for the accurate measurement of the absorption and transmission of light by semi-transparent substances and used for the determination of turbidity, fluorimetry, etc.
Abstract means theoretical rather than practical.
Acardia is the condition of a person born without a heart.
An accelerating electrode is an electrode in an electron tube which is maintained at a positive potential with respect to the cathode and any other electrodes situated between the cathode and the accelerating electrode, thus imparting acceleration to electrons in the direction away from the cathode. Although this definition includes the anode of the tube, the term is usually reserved for accelerating electrodes other than the anode.
In electronics, an accelerating grid is an accelerating electrode in the form of a grid.
Acceleration is the rate at which a moving body increases in velocity.
An accelerator is a device for increasing speed.
An accelerator valve is a thermionic valve employed as a particle accelerator.
An accelerometer is an apparatus, either mechanical or electromechanical, for measuring acceleration or deceleration - that is, the rate of increase or decrease in the velocity of a moving object. Accelerometers are used to measure the efficiency of the braking systems on road and rail vehicles; those used in aircraft and spacecraft can determine accelerations in several directions simultaneously. There are also accelerometers for detecting vibrations in machinery.
An accent is a local mode of pronunciation in speech.
An accolade is a gentle blow on the shoulders with the flat of a sword given by a Sovereign or his representative in conferring knighthood to the recipient.
An accomplice is someone associated with somebody else in the committing of a crime.
An accordion is a small portable musical instrument with a keyboard and bellows. It was invented by Damian in 1829.
Accounts are a statement of income and expenditure.
In electrical terms, an accumulator stores electrical energy.
An ace is a playing card with one pip.
In tennis terms an ace is a non-returnable serve.
Acetal is a colourless liquid formed by oxidation of alcohol.
Acetaminophen is a drug used to treat mild pain or fever. It has the possible side effects of: Rash, itching and severe liver damage with over dosing.
Acetic acid is an organic acid with the formulae ch3cooh.
see "Ethyl Acetate"
Acetone is a colourless liquid with the formulae ch2coch3.
Acetylene is a highly inflammable gas of the hydrocarbon family used for welding and cutting metals. It was discovered by Berthelot. In 1862 Wohler discovered that carbide of calcium treated with water produced lime and acetylene. In 1895 acetylene was cheaply produced on a commercial scale and subsequently was used for general lighting.
Achor is (was?) a disease of infants, in which the head, face and breast become encrusted with thin, yellowish or greenish scabs.
An achromatic telescope is a telescope in which colour is got rid of. They were invented by Jogn Dollond around 1753.
An acid is a chemical compound that reacts with metals to form salts by releasing hydrogen.
In telecommunications, ACK is the ''acknowledge'' character in many data codes; used most commonly for an affirmative response of correct receipt.
The aclinic is a magnetic equator.
Acne is a skin eruption due to inflammation of the sebaceous glands.
Aconitine is a poisonous alkaloid derived from aconite.
An acorn valve is a form of thermionic valve used at ultra-high frequencies, in which, by adopting very small dimensions and special constructions, the inter-electrode capacitances, lead inductances and transit time effects are greatly reduced.
The term acoustic refers to hearing.
Acoustic feedback is the return of acoustic energy from the output of a sound reproducing equipment, such as a microphone-amplifier-loudspeaker combination, to the input or to an intermediate stage, thereby causing the system to generate sustained oscillations which are manifested as continual howling.
An acre is an ancient measurement of land area being (since 1824) 4840 square yards. Prior to that Edward I introduced the first standard for the acre in Britain.
Acridine is an organic compound with the formulae c13h9n used in dyes and drugs.
Acriflavine is an antiseptic powder.
Acromegaly is a disease due to over activity of the pituitary gland results in excessive bone growth, especially the skull.
An acronym is a word formed from the initials of other words.
Acrophobia is the fear of high places.
The acropolis was the citadel of ancient Greek cities.
An acrostic is a poem in which the first or last letters of each line, read downwards, form a word or sentence. Double acrostics became very popular in 1867.
Acrylic is a synthetic fibre derived from acrylic acid.
The Act of Succession in 1534 declared the marriage of Henry VIII and Catherine of Aragon null and void, and settled the succession to the throne on the heirs of Henry VIII by Anne Boleyn.
An actinide is an element with an atomic number between 89 and 103.
Actinium is a radioactive element with the symbol Ac.
An actinometer is an instrument for measuring heat radiation.
The Acts of Supremacy were passed in 1534 enacting that the King (Henry VIII) was the only supreme head on earth of the Church of England, with power to redress all heresies and abuses.
Adaptive Equalisation is a telecommunications term referring to the equalisation of received digital signals capable of adjustment during actual transmission.
an Adcock aerial is a radio aerial system consisting of two vertical open-spaced dipoles with screened horizontal connections. It thus responds almost exclusively to the vertically polarised component of a received wave and is used for radio direction finding.
Addiscombe College was a college near Croydon, Surrey, which was purchased by the East India Company in 1809, for the education of candidates for scientific branches of the Indian army. It was closed in 1861.
Addison's Disease is a dangerous affection of the renal capsules. It was first described by Thomas Addison in 1855.
An adhesive is a sticky substance.
Adipocere is a substance in dead bodies formed by decomposition of fatty acids when exposed to moisture.
An adit is the horizontal entrance to a mine.
The admiralty was the board of state charged with the provision, organisation and control of the royal navy. It was founded by Henry VIII and amalgamated in 1964 into the ministry of defence.
An adobe is a Mexican house made of clay bricks.
An adult is a fully grown being.
An adytum is the inner most part of a temple.
An adze is a carpenter's tool for cutting away the surface of wood.
The Aelfric Society was founded in 1842 to publish the Homilies of Aelfric, archbishop of Canterbury and other Anglo-Saxon works. It closed in 1856.
The aeolopile is a hollow ball with an orifice where a tube might be screwed. It was used in the 17th century as a boiler for experimental steam-engines. A similar apparatus is described by Vitruvius in the first century, and its invention is generally attributed to Hiero of Alexandria.
An aeon is an immeasurable period.
Aerated water (soda water) is a solution of carbonic acid in water. It was discovered by Priestly and suggested as a prevention of scurvy, a paper being presented to the Admiralty in 1773. Certainly sailors drank aerated water on board ship as a bottle was found from the Royal George which sank in 1780.
An aerial is a receiving or radiating device used in radio communications.
An aerodrome is a place where aircraft are based.
The aerophore was an apparatus invented by Denayrouze to enable persons to enter a noxious inflammable atmosphere. It comprised an air-pump, lamp, and flexible tubing. It was tried at Chatham in January 1875 and was reported successful.
Afrikaans is a language used in the Republic of South Africa.
Agar is a laxative substance obtained from seaweed.
An agenda is a list of tasks.
Aggry Beads are glass beads prized by West African natives as ornaments and having magical and medicinal powers.
Agoraphobia is the fear of open spaces.
The Agricultural Children Act of 1873 prohibited the employment of children under eight years of age, and provided for the education of older children.
Agricultural Hall is a building in Islington, London. Work commenced on it in 1861, and it opened in 1862 for an exhibition of dogs. It was constructed chiefly for the meetings of the Smithfield Club.
The air is a mixture of gasses enveloping the earth.
An aircraft is a flying machine, a vessel which flies through the air rather than floats on water or travels along a road or rail.
An aisle is a passage between rows of seats.
Albugo is an affection of the eye, consisting of a white opacity in the cornea.
Alchemy was the medieval forerunner to chemistry.
Alcohol is a volatile liquid derived from hydrocarbons.
Aldehyde is a chemistry term applied to the compounds of alcohol intermediate between the alcohols and the acids.
Ale is an alcoholic drink made from malt and hops.
An aleurometer is a device used in bread making for measuring the quality of wheaten flour.
Algebra is a division of mathematics dealing with relations.
ALGOL is an algebraic computer language.
An algorithm is a set of rules.
An alkali is a chemical substance.
The alkaloids are nitrogenous organic substances.
The alkanes are the paraffin series of hydrocarbons.
An alkene is a member of the ethylene series of hydrocarbons.
Alkyl refers to a substance which is derived from or related to the paraffin series of hydrocarbons.
An allergy is a hypersensitivity of body tissue to a substance.
An alley is a narrow street.
The Allies were various countries that fought the Axis forces in the Second World War.
An alloy is a mixture of a metal and other metals or non-metals.
Alluvium is river transported deposits of mud, sand and gravel which accumulate to form distinctive features such as levees, flood plains and deltas.
Alpha is the first letter of the Greek alphabet.
Alpha Particles are the nuclei of the atom of helium, comprising two neutrons and two protons, and thus exhibiting a positive electric charge.
Alpha Rays are a stream of swiftly moving alpha particles. An alpha ray is capable of ionizing gases and of producing fluorescence in certain substances.
see "Vitamin E"
An alphabet is an ordered series of letters used in language.
An altar is a block used for making offerings to a deity.
Alternating current is electric current which changes direction rhythmically, rising from zero to a maximum in the positive direction, falling to zero again and then increasing to a maximum in the negative direction before returning again to zero, after which the cycle repeats. The number of cycles per second is the frequency of the alternating phenomenon. British domestic alternating current exhibits 50 cycles per second, where as American domestic alternating current exhibits 60.
The althing is the parliament of Iceland, it was created in 930 and is the oldest parliamentary assembly in the world.
An altimeter is a device measuring altitude.
Altitude is height above mean sea level.
Aluminium is a light-weight silvery metal element with the symbol Al.
Alundum is a form of aluminium oxide used in the manufacture of thermionic valves for insulating the cathode heater from the tubular cathode.
The Amazon was a West India mail steam ship. She left Southampton on her first voyage on Friday 2nd of January 1852 and on Sunday morning, January 4th, she was destroyed by fire at sea, about 175 km west-south-west of Scilly. Of 161 persons on board 102 perished.
Ambaree is a fibre similar to jute and largely used in India. It is obtained from Hibiscus cannabinus.
Amber is fossilised resin.
Ambergris is a substance derived from the intestine of the sperm whale and used in perfume.
Ambidextrous is having the facility to use the left hand as effectively as the right.
Amenorrhoea is a medical condition being the absence or suspension of menstruation.
American is a term referring to someone or something which comes from, or is found in, America.
Americium is a synthetic chemical element with the symbol Am that is the most frequently used element for superconducting devices. It is artificially produced from plutonium, and is used commercially in gauges, distance-sensing devices, and smoke alarms. Americium was first synthesized in a nuclear reactor in 1944 by Glenn Seaborg, Ralph James, Leon Morgan, and Albert Ghiorso.
An amice is a white linen vestment worn by Roman Catholic and many Anglican priests when officiating at Mass or Holy Eucharist.
Amines are a class of compounds derived from ammonia by the replacement of one or more hydrogen atoms with organic groups.
Amino acids are fundamental constituents of all proteins.
An ammeter is a device for measuring electrical current.
Ammonia is a colourless gas. Formulae nh3.
Ammonium is the basic radical of ammonium salts. It is comprised of one atom of nitrogen and four atoms of hydrogen.
Ammonium Chloride (Sal Ammoniac) is a fibrous mass prepared by neutralising ammonia with hydrochloric acid. It is used in medicine, dyeing and soldering. It has the formulae NH4Cl.
Amoxicillin trihydrate is a drug used to treat systemic infections and acute and chronic urinary tract infections. It has the possible side effects of: Nausea, vomiting, diarrhea, hypersensitivity (rash) and itching.
The ampere is the fundamental unit of measurement of electrical current.
Amphetamine is a drug that induces sleeplessness.
An amphitheatre is a circular or ovular arena surrounded by tiers of seats.
Ampicillin trihydrate is a drug used to treat systemic infections and acute and chronic urinary tract infections. It has the possible side effects of: Nausea, vomiting, diarrhea, glossitis (inflammation of the tongue), stomatitis (inflammation of the mouth), hypersensitivity (rash) and itching.
An amplifier is an apparatus capable of producing a magnified version of the input signal.
Amplitude refers to magnitude or size. It is the voltage or power of an electronic signal.
Amplitude Modulation is modifying a ''carrier'' signal by varying its instantaneous power to represent the information it carries. Most commonly called ''AM''.
Amyl is a chemical alcohol radical. It was first isolated by Edward Frankland in 1849.
Amylene is a colourless, mobile liquid first procured by Balard of Paris in 1844 by distiling fusel oil with chloride of zinc. The vapour was employed instead of chloroform first by Snow in 1856.
Amylum is an alternative name for starch.
The Anabaptists were a 16th century Christian sect, so called because they rejected infant baptism in reference of adult baptism. They were a fanatical sect led by Nicholas Storck who intended reorganisation of German society based upon civil and political equality.
Anaemia is the medical condition of lacking red blood cells.
An analgesic is a pain reliever.
An analogue computer is a computing device in which the variables in a given problem are represented by physical quantities, such as lengths, pressures, electric charges etc., the calculations consisting in the manipulation and measurement of these quantities, the values of which may change continuously.
Anatomical alloy is a fusible alloy consisting of 53.5 per cent bismuth, 19 percent tin, 17 per cent lead and 10.5 per cent mercury.
An anchor is a heavy implement used for securing boats at sea.
Andante is a musical term denoting a movement somewhat slow, graceful, distinct and soothing.
An anemometer is a device for measuring the strength and velocity of wind. It was invented by Wolfius in 1709.
An angiosperm is a flowering plant in which the seeds are enclosed within an ovary which ripens into a fruit.
Angst is an emotional state of anxiety without a specific cause.
The Angstrom Unit is a unit of length employed for the measurement of the wavelengths of light and X-rays etc.
Aniline (Phenylamine) is an oily liquid made by the reduction of nitro-benzene and used in the manufacture of chemicals, dyes and drugs. It was discovered in 1826 by Unverdorben among the products of distillation of indigo. In 1856 Bechamp obtained it from nitro-benzene.
An anion is a negatively charged ion which, in an electrolye or in a gas-filled space, travels towards the positive electrode or anode.
The anker was a measurement used in Britain and Germany for beer, spirits and the like. It was equivalent to 8.5 gallons.
Annuity tax was a tax levied to provide stipends for ministers in Edinburgh and Montrose, it caused much disaffection and was abolished in 1860, and other provisions made for the purpose. These proved equally unpopular and their abolition was provided for by an act passed in 1870.
An anode is the principal positive electrode by which the current leaves an electrolyte, electron tube etc.
The anorthoscope is an optical apparatus described by Carpenter in 1868. In it distorted figures lose their distortion when in rapid motion.
Anosmia is the inability to smell.
ANSI is the American National Standards Institute. The official repository of standards for the USA.
Anthrax is a disease of sheep and cattle transmittable to humans.
Anthropology is the study of humans as animals.
Antiarin is a poison exuded by the Upas tree and used by Javan natives for tipping arrows.
An antibiotic is a substance that inhibits the growth of micro organisms.
An antidote is a drug used to counteract poison.
Antimony is a brittle, silver-white, pentavalent metal element with the symbol Sb.
Antipyrine is an artificial alkaloid obtained from coal-tar and discovered in 1883 by Knorr. It was said to be a remedy for sea-sickness, a substitute for quinine and a source of aniline colours.
An antiseptic is a substance which counteracts blood or tissue poisoning caused by bacteria (sepsis).
An anvil is a block used by metal smiths.
An anxiolytic is a drug used to reduce anxiety.
Apartheid is the policy of racial segregation of people. It was first established in South Africa in 1948 restricting the rights of non-whites and establishing blacks only homelands.
In photography, an aperture is an opening through which light passes through the lens to strike the film.
Aphasia is difficulty in reading, writing and speaking due to brain damage.
The aphelion is the point at which an object travelling around the sun in an elliptical orbit is at its furthest from the sun.
Apogee is an astronomical term referring to the position in the orbit of the Moon which is farthest from the Earth. Opposite to Perigee.
The apollo asteroids are a group of small asteroids whose orbits cross that of the earth. They were first discovered in 1932 and then lost until 1973.
The Apollo Project was the US space project to land a person on the moon. It was achieved by Apollo 11 in July 1969.
Apostle spoons were spoons with figures of the apostles crowning the handles. They were given as baptismal presents during the 16th and 17th centuries.
Applique is a type of embroidery used to create pictures or patterns by applying pieces of material to a background fabric.
Aqua is another word for water.
Aquatint is a method of print-making which was popular in the 18th century.
An aqueduct is a channel in which water flows by gravity.
Aqueous refers to a solution based upon water.
The archeozoic period was the first geological period. It was characterised by an absence of animal life and extensive volcanic activity.
An archipelago is a group of islands.
Arcnet is a LAN architecture developed by Datapoint Corporation featuring low cost for connection of groups of (Async) terminals to a (mini) computer within a premises.
An areometer is an instrument for measuring the density and specific gravity of liquids.
An arete is a steep angular mountain ridge.
Argon is an inert gaseous element found in the air with the symbol Ar.
Aries is one of the signs of the zodiac. Represented by the ram.
An armature is a part of an electrical motor or dynamo.
Armour is a protective covering.
Arms is a military term referring to weapons.
An army is an organised fighting force.
Arroba was a Spanish unit of weight equal to about 25 lbs. It was also used in South and Central America, where it was equivalent to about 32 lbs.
An arsenal is a place for storing weapons.
Arshin is a Russian unit of measurement equivalent to 28 inches.
ASCII is the American Standard Code for Information Interchange.
The most common code used for asynchronous data transmission by minicomputers and personal computers. Derived from the TWX code of the Bell Model 28 teleprinter, expanded to use all possible character combinations.
ASCII consists of 7 information bits with an 8th parity bit for error checking; numerous variations exist, for example use of the 8th bit in personal computers to extend the code with a number of graphics, special language characters and diacritical marks. Many common carrier data services cannot transmit the 8th bit needed to use that common PC extension of ASCII's alphabet.
Ash Wednesday is the first day of lent, the seventh Wednesday before Easter.
Asphalt is a material used for road coverings.
Aspirin is an analgesic.
Assay is the testing of an alloy or an ore to determine the proportion of a given metal. An assay officer is someone who certifies the fineness of gold, silver and platinum.
Assize of Battle was by the old law of England, a means whereby a man charged with murder might fight with the appellant, thereby to make proof of his guilt or innocence. The law was struck off the statute book in 1819.
Association Football is a variation of football played at Cambridge in the first half of the 19th century. A code of rules forbidding the use of hands was drawn up in 1863, and officially adopted by the Football Association, the governing body of the game, which was formed in the same year. Association football is played by teams of 11 a side with a spherical inflated leather ball 27-28 inches in circumferance and about 14 ounces in weight. The ground is 120 yards long and 80 yards wide having a goal at each end 8 yards wide with a cross bar 8 feet above the ground. The match is played in two halves each of 45 minutes with a 5 minute interval at half-time.
Astatine is an element with the symbol At
Astern is a nautical term meaning behind the ship.
An asteroid is a minor planetary body.
Asthma is a disease characterised by breathing difficulties.
Astrology is the science of the relationship between events and the stars.
Astronomy is the study of celestial bodies.
Asynchronous refers to occurring without central control or in an unpredictable time interval between successive elements; the typical mode of telegraphy, minicomputers and personal computers; requires s transmission of ''start'' and ''stop'' bits to provide decoding synchronisation at the receiver.
Athletics is the sport of physical games.
Atmolysis is a method of separating the constituent gases of a compound gas (such as air) by causing it to pass through a vessel of porous material (such as graphite). The process was discovered by Graham and made known in 1863.
The atmosphere is the gaseous envelope surrounding a planet, such as that which surrounds the earth which is comprised of nitrogen, oxygen, argon carbon dioxide, helium, water vapour and other gases.
An atoll is a circular, or horseshoe-shaped coral island surrounding a lagoon with one or more openings to the sea.
An atom is the smallest quantity of a chemical element which can enter into combination or take part in a chemical reaction.
The atrium was the entrance hall to a Roman house.
Atropine is the poisonous alkaloid found in deadly nightshade.
Attenuation is a term denoting a decrease in power between that transmitted and that received due to loss through equipment, lines, or other transmission devices. Usually expressed as a ratio in dB (decibels). - Synonym: Loss; Antonym: Gain
In electronics, an attenuator is a network used to deliberately reduce the input signal to some piece of apparatus, or to reduce the degree of amplification of signals of particular frequencies.
The audiphone was an early hearing-aid invented by Rhodes and improved in 1880 by Colladon. It consisted of a thin sheet of hard ebonite rubber or cardboard placed next to the teeth through which and other bones sound vibrations are conveyed to the auditory nerve.
The month of august was the sizth month of the Roman calendar and was originally called Sextilis, by a decree of the senate it received its present name in honour of Augustus Caesar in 8 BC.
Avenin is a stimulating nitrogenous alkaloid found in oats.
The avoirdupois scale is a measurement of weight.
An axe is a metal tool for chopping and cleaving.
Azoimide is a compound of hydrogen and nitrogen. It is a very explosive gas obtained from organic sources such as benzoyl-glycollic acid and hippuric acid.