The phase of intermediary metabolism concerned with the energy-requiring biosynthesis of cell components from smaller precursors.
Anacoustic Zone
The region above an altitude of about 100 miles where the distance between the air molecules is greater than the wavelength of sound, and sound waves can no longer be propagated.
An organism that lives without oxygen and uses another chemical species as a terminal electron acceptor.
Occurring in the absence of air or oxygen.
Anaerobic Adhesive
An adhesive which hardens in the absence of air, such adhesives are often used as a thread locking medium.
Any representation of a physical quantity in terms of a continuous variation of a second physical quantity.
Analogue Computer
Ranging in complexity from a slide rule to electrical computers used for solving mathematical problems.
Analogue to Digital converter
A circuit that converts an analog signal, having a continuously varying amplitude, to a digitally quantized representation using binary output signals.
An Analyser is another name for a secondary polariser in an optical system.
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Analysis Books
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Analysis Calculations
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Analysis Conversions
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The sample constituent whose concentration is sought in a chemical analysis.
Distorted, as in an optical system with different magnification levels or with focal lengths perpendicular to the optical axis.
Anaplerotic Reaction
An enzyme-catalyzed reaction that can replenish the supply of intermediates in a metabolic pathway, most commonly the citric acid cycle.
This is an electronic method of reducing or removing unwanted sound by the production of a pressure wave of equal amplitude but opposite sign to the nwanted sound.
A weighty grappling hook used for holding a ship fast.
Anchor Bolt
A special type of bolt used to attach objects or structures to concrete.
A secure fixing.
Name given to components such as alternator, power steering pump and air conditioning compressor driven by the engine.
In Boolean algebra, the operation of intersection.
AND Gate
Gate that produces a logic 1 when all of its inputs are 1. In all other cases the output is 0.
Volcanic rock characteristically medium dark in colour and containing 54 to 62 percent silica and moderate amounts of iron and magnesium.
Without echo.
Anechoic Chamber
A room whose boundaries effectively absorb all incident sound over the frequency range of interest, thereby creating essentially free field conditions.
The property of a solid in which deformation depends on the time rate of change of stress as well as on the stress itself.
A sensor that measures wind speed.
Aneroid Barometer
An instrument used to measure atmospheric pressure consisting of an evacuated container with a flexible wall.
Angelic Acid


A monocarboxylic unsaturated organic acid found in Angelica Archangelica as well as other plants.

Angle Bisector
A ray that divides an angle into two congruent angles.
Angle Grinder
A handheld powered tool with a geared head at a right-angle on which is mounted an abrasive disc.
Angle Iron
An iron or steel structural member that has been cast, rolled, or folded so that its cross section is L-shaped.
Angle Modulation
Modulation in which the angle of a sine-wave carrier is varied by a modulating wave.
Angle of Arrival
A measure of the direction of propagation of electromagnetic radiation upon arrival at a receiver.
Angle of Attack
The angle at which a wing strikes the air stream.
Angle of Climb
The angle between the flight path of a climbing vehicle and the local horizontal.
Angle of Depression
The angle in a vertical plan between the local horizontal and a descending line.
Angle of Descent
The angle between the flightpath of a descending vehicle and the local horizontal.
Angle of Deviation
The angle through which a ray is bent by refraction.
Angle of Elevation
The angle between the horizon and a point above the local horizon in the celestial sphere, measured along the great circle that passes through both the zenith and the point in question.
Angle of Incidence
Angle between direction of motion of waves and a line perpendicular to the surface the waves are striking.
Angle of Pitch
The angle, as seen from the side, between the longitudinal body axis of an aircraft or similar body and a chosen reference line or plane, usually the horizontal plane.
Angle of Reflection
Angle between direction of motion of waves and a line perpendicular to surface the waves are reflected from.
Angle of Refraction
The angle at which a refracted ray of energy leaves the interface at which the refraction occurred.
Angle of Repose
The maximum angle at which loose material will come to rest when added to a pile of similar material.
Angle of Roll
The angle that the lateral body axis of an aircraft or similar body makes with a chosen reference plane in rolling; usually the angle between the lateral axis and a horizontal plane.
Angle of Yaw
The angle, as seen from above, between the longitudinal body axis of an aircraft, rocket, or the like and a chosen reference direction.
Angle Plate
A precision holding fixture made of cast iron, steel, or granite.
Angled Screwdriver
An angled screwdriver is useful when there is not enough space to get access to with a normal straight screwdriver.
The inclination of one line to another.
It is an old unit used for measuring the wavelength of electromagnetic radiation including visible light and X-rays.
Angstrom Anders, Jon
Swedish physicist and one of the pioneers of spectroscopy.
Angstrom Star
Unit used to measure the wavelength of X-rays.
Angular Acceleration
The rate of change of angular velocity.
Angular Displacement
The amount of rotation of a point, line, or body in a specified direction about an axis.
Angular Frequency
The frequency of a steady recurring phenomenum in radians per second.
Angular Momentum
A vector quantity giving the rotational momentum.
Angular Momentum Quantum Number
A quantum number that labels the subshells of an atom.
Angular Rate
The rate of change of angle.
Angular Rate Sensor
A sensor that measures rotational velocity around its sensitive axis.
Angular Speed
The rate of change of angle turned in radians.
Angular Velocity
The rate of change of angle turned in radians.
The angle between two shaft centrelines. This angle is the same at any point along either centreline. It is normally specified in rise/run.
Of or pertaining to an oscillating system that is not undergoing simple harmonic motion.
The angle between an aerofoil and the horizontal when the wing is inclined downwards from its mounting.
A compound with all water removed, especially water of hydration.
Also known as Phenylamine or aminobenzene.
Aniline Number
Lowest temperature at which equal parts of aniline and a sample of oil are completely miscible.
Animal Glue
A mixture of animal by products rendered down and dried to a hard jelly like consistency.
Ions with a negative charge.
A sequence of events where the time seperating each pair is not equal.
Also known as Methyl Phenyl Ether, an aromatic smell and used in perfumes.
Unequal physical properties along different axes.
Heating to and holding at a suitable temperature and then cooling at a suitable rate, for such purposes as reducing hardness.
Annealing Twin
A twin formed in a crystal during recrystallization.
A process in which a particle meets its corresponding antiparticle and both disappear.
Annihilation Radiation
Electromagnetic radiation produced by the coalescence and mutual annihilation of a positron and an electron.
Anno Domini
Latin for "year of the Lord," the traditional designation for years of the common or Christian era.
Annual Aberration
The component of stellar aberration resulting from the motion of the Earth about the Sun.
Pertaining to an annulus or ring; ring shaped.
Annular Eclipse
An eclipse in which a thin ring of the source of light appears around the obscuring body.
The region enclosed by two concentric circles.
The electrode where electrons are lost (oxidized) in redox reactions.
Anode Corrosion
The dissolution of a metal acting as an anode.
Anode Effect
A condition in an electrolytic cell that produces an abrupt increase in cell voltage and a decrease in current flow.
Anode Mud
The insoluble residue that derives from the anodic dissolution of an impure metal such as copper during electrorefining.
Anode Slime
Another name for Anode Mud.
Anodic Metal
Any metal that tends to dissolve, corrode, or oxidize in preference to another metal when the metals are connected electrically in the presence of an electrolyte.
Anodic Protection
A technique to reduce the corrosion rate of a metal by polarizing it into its passive region, where dissolution rates are low.
Anodic Reaction
Electrode reaction equivalent to a transfer of positive charge from the electronic to the ionic conductor; an anodic reaction is an oxidation process.
To coat a metal with a protective film by electrolysis.
A medicine or drug which alleviates pain.
The electrolyte on the anode side of an electrochemical cell that is divided into compartments.
Anomalistic Month
The average period of revolution of the moon from perigee to perigee, a period of 27 days 13 hours 18 minutes 33.2 seconds.
Anomalistic Year
The period of one revolution of the earth about the sun from perihelion to perihelion.
Anomalous Dispersion
A sudden change in the refractive index of a material for wavelengths in the vicinity of absorption bands in the spectrum of the material.
A neurological disorder which causes a marked inability to name otherwise familiar stimuli.
A complete lack of oxygen available for physiological use within the body.
Abbreviation of American National Standards Institute.
A length of wire or similar that radiates (such as a transmitting antenna) or absorbs (such as a radio antenna) radio waves.
Antenna Aperture
A surface, near or on an antenna, on which it is convenient to make assumptions regarding the field values for the purpose of computing fields at external points.
Antenna Array
A system of antennas coupled together to obtain directional effects, or to increase sensitivity.
Antenna Beam Width
Width of a radar beam measured between half-power points.
Antenna Coupler
A device used for impedance matching between an antenna and a transmitter or receiver.
Antenna Diversity
The technique of using more than one antenna to ensure that the received signal strength is always maximized.
Antenna Pattern
A representation, usually in the form of a polar or rectangular plotted graph, of the radiated field intensity of an antenna.
Antenna Regions
The distinction between electromagnetic fields far from, and those near to, the antenna.
A family of pigments that give flowers, fruits, and leaves of some plants their red or blue colouring.
White crystalline with a blue fluorescence used in the manufacture of dyes.
Type of coal with highest carbon content (86% to 98%) and thus highest heat value .

Anthracite Iron
The substance created by the smelting together of anthracite coal and iron ore.

Yellow powder derived from Anthracene and used as a dye.
Anthropic Principle
Principles describing what conditions are necessary for the development of intelligent life.
Resulting from or produced by human beings.
Anthropogenic Emissions
Emissions of greenhouse gases, greenhouse gas precursors, and aerosols associated with human activities.
Anti Dive Suspension
Front suspension kinematic characteristic which reduces the amount of pitch under braking forces.
Anti Lift Suspension
Rear suspension kinematic characteristic which reduces the amount of pitch under braking forces.
Anti Lock Brake System
A system that can modulate the brake pressure under hard braking conditions to avoid a brake locking and resultant skidding.
Anti Reflection Coating
A thin layer of material that, when applied to a lens, increases its transmittance and reduces its reflectance.
Anti Resonance
In multi degree of freedom systems or continuous systems there will exist frequencies at which a dynamic force applied at a point will not cause any motion of the system at that point.
Anti Squat Suspension
Rear suspension kinematic characteristic which reduces the amount of pitch under acceleration.
Anti-Aliasing Filter
A device that attenuates signal content outside the desired bandwidth.
An atom of antimatter.
The antiparticle of a baryon.
An organic compound secreted by many species of microorganisms and fungi which is toxic to other species.
A protein produced by the body′s immune system in response of an invading substance or organism.
Antibonding Molecular Orbital
Also known as Antibonding Orbital.
Antibonding Orbital
A molecular orbital that can be described as the result of destructive interference of atomic orbitals on bonded atoms.
A chemical compound that reacts with chlorine-based bleaches to stop the bleaching.
A specific sequence of three nucleotides in a tRNA, complementary to a codon for an amino acid in a mRNA.
A relative pressure maximum. An area of pressure that has diverging winds and a rotation opposite to the earth′s rotation.
Anti-Dive Suspension
The resistance to a vehicle's tendency to dip down in front when the brakes are applied.
The anti particle of an electron.
Alternative name for Acetanilide.
A phenomenon observed in some materials in which complete magnetic moment cancellation occurs as a result of antiparallel coupling of adjacent atoms or ions.
Compounds of glycol or alcohol, that lower the freezing point of cooling water systems.
Anti-Friction Bearing
An anti-friction bearing is a bearing utilizing rolling elements between the stationary and rotating assemblies.
Any molecule which causes the synthesis of a specific antibody in vertebrates.
The antiparticle of a lepton.
x=by is called the antilogarithm of y to the base b.
Material made from antifermions. We define the fermions that are common in our universe as matter and their antiparticles as antimatter.
Antimonic Chloride
Alternative name for Antimony Pentachloride.
Antimonous Chloride
Alternative name for Antimony Trichloride.
Antimonous Oxide
Alternative name for Antimony Trioxide.
Alternative name for Antimony Triselenide.
Elemental antimony is generally found in one of two allotropes and has both metallic and non-metallic properties.
Antimony Hydride


Poisonous gas. Also known as Stibine.

Antimony III Chloride
Alternative name for Antimony Trichloride.
Antimony Pentachloride


Toxic, very corrosive and fumes in moist air. It is a reddish-yellow, oily liquid, which is hygroscopic and solidifies after moisture is absorbed.

Antimony Pentafluoride


Colourless, viscous liquid that is a valuable Lewis acid and a component of the superacid fluoroantimonic acid, the strongest known acid. Some features that give the compound scientific interest are its Lewis acidity and that it also reacts with almost all known compounds.

Antimony Pentoxide
Alternative name for Antimony V Oxide.
Antimony Perchloride
Alternative name for Antimony Pentachloride.
Antimony Quintachloride
Alternative name for Antimony Pentachloride.
Antimony Sesquioxide
Alternative name for Antimony Trioxide.
Antimony Tetroxide

Sb2O4, SbO2

An inorganic compound.

Antimony Tribromide


Added to polymers such as polyethylene as a fire retardant

Antimony Trichloride


The soft colorless solid with a pungent odor was known to the alchemists as butter of antimony.

Antimony Trifluoride


A light grey crystalline material often used in dyeing and pottery.

Antimony Triiodide


Used as a dopant in the preparation of thermoelectric materials.

Antimony Trioxide


The most important commercial compound of antimony.

Antimony Triselenide


Exists as the sulfosalt mineral antimonselite.

Antimony V Oxide


Used as a flame retardant in ABS and other plastics, a flocculant in the production of titanium dioxide and is sometimes used in the production of glass, paint and adhesives.

The antiparticle of a neutrino.
The antiparticle of the neutron.
Point of maximum displacement.
Antiproton or an antineutron.
Compounds that slow oxidation processes that degrade foods, fuels, rubber, plastic, and other materials.
Another name for Antiozonant.
Substances that reverse or prevent severe oxidation by ozone.
A subatomic particle with the same-size properties as those of the particle although some may have the opposite sign.
Cotransport of two solutes across a membrane in opposite directions.
The antiparticle of the proton.
A substance that can lessen or prevent fever.
The antiparticle of a quark.
Anti-Roll Bar
A bar between the two wheels on an axle used to control roll by attempting to keep the two wheels at the same position in bump / rebound.
Anti-Single Phase Tripping Device
A device that operates to open all phases of a circuit by means of a polyphase switching device, in response to the interruption of the current in one phase.
Antisolar Point
The point on the celestial sphere 180° from the sun.
A measure of a vehicle′s resistance to rear suspension squat due to weight transfer during acceleration.
Of or pertaining to the ability to either prevent the accumulation of or to enable the dissipation of static charge.
Antitransmit Receive Tube
A tube that isolates the transmitter from the antenna and receiver.
Substances that reverse or prevent severe oxidation by ozone.
Antoine Equation
A simple 3-parameter fit to experimental vapour pressures measured over a restricted temperature range.
A heavy iron or steel block upon which metal is forged or hammered.
An elementary particle or particle-like excitation having properties intermediate between those of bosons and fermions.