Beryllium is a light and lustrous metal that is resistant to attack by air or water, even at elevated temperatures
Chemical formula of Beryllium Nitride.
Temporary accumulations of sediments that collect between low and high tide marks.
A device which serves as a signal emitter for use as a guidance or warning aid.
A rigid structural element.
Beam Bridge
A simple type of bridge, composed of horizontal beams supported by vertical posts.
Beam Compass
A setting out tool that is used for scribing circles and arcs.
Beam Power Tube
An electron tube in which the grids are aligned with the control grid.
Beam Splitter
An optical device using controlled reflection to produce two beams from a single incident beam.
Beam Steering
The method of steering the main lobe of a transducer to a certain direction.
Beam Width
The width of the main beam lobe, in degrees, of the transducer. It is usually defined as the width between the "half power point" or "-3dB" point.
Primarily two types, rolling element and sleeve or plain bearing.
Bearing Life
Defined as the length of time, or the number of revolutions, until a fatigue spall of a specific size develops.
Bearing Misalignment
A misalignment that results when the bearings supporting a shaft are not aligned with each other.
Bearing Nomenclature
Codes specific to the bearing manufacturer that describe the material, clearance, construction and other factors.
Bearing Partition
A partition that supports any vertical load in addition to its own weight.
Bearing Plate
A metal plate that provides support for a structural member.
Bearing Resolution
Ability of a radar to distinguish between targets that are close together in bearing.
Bearing Wall
A wall that supports a weight above in additional to its own weight.
Beat Frequency Oscillator
An oscillator whose output is intended to be mixed with another signal to produce a sum or difference beat frequency.
Periodic fluctuations that are heard when sounds of slightly different frequencies are superimposed.
Beaufort Scale
In 1805 Admiral Beaufort drew up a scale of wind strengths related to commonly observable phenomena.
Chemical formula of Beryllium Bromide.
Chemical formula of Beryllium Chloride.
The Becquerel is a unit used to measure a radioactivity. One Becquerel is that quantity of a radioactive material that will have 1 transformations in one second.
Becquerel, Antoine-Henri
Discovered natural radioactivity and shared the Nobel Prize for physics for this discovery.
One of the principal parts of a machine tool, having accurately machined ways or bearing surfaces for supporting and aligning other parts of the machine.
Bed Moulding
A moulding in an angle, as between the overhanging cornice, or eaves, of a building and the sidewalls.
The lower part of the engine resting on the foundation.
A general term for solid rock that lies beneath soil, sediments, or other unconsolidated material.
A very hard wood almost unaffected when exposed to water. Therefore, it is used for keels of ships and flood gates. On account of its hardness it was used for wheels and railway sleepers.
Produced by bees to make their honeycombs.
Chemical formula of Beryllium Fluoride.
Behaim, Martin
Mapmaker, navigator, and merchant who made the earliest globe, called the "Nürnberg Terrestrial Globe".
Behavioural Envelope
Envelope of response versus frequency.
Chemical formula of Beryllium Iodide.
The bel is the logarithm of the ratio of two powers, and the decibel is one tenth of a bel.
Belgian Truss
Structural framework for supporting loads over long spans.
Traditional unit of time used on ships. There are 8 bells in one watch of 4 hours.
Bell, Alexander Graham
Invented the telephone with Thomas Watson in 1876. Bell also improved Thomas Edison′s phonograph.
Bell Crank
A lever that can be used to change the direction of a linear motion.
Bell Curve
A continuous probability distribution that often gives a good description of data that cluster around the mean.
Bell, Henry
Scottish engineer and inventor who built a steam-powered boat.
Bell Metal
Copper tin alloy with much higher tin content than conventional bronze in order to make it hard and sonorous. It is too brittle to be used for many other applications.

Bell Mouth
The flaring or tapering of a machined hole, usually made at the entrance end because of misalignment or spring of the cutting tool.
Corrugated cylindrical container which moves as pressures change, or provides a seal during movement of parts.
Bellows Seal
A type of mechanical seal which utilizes bellows for providing secondary sealing and spring-type loading.
Bells′ Inequality
A quantum mechanical theorem which demonstrates that quantum mechanics must have nonlocal properties.
Belt Course
A horizontal board carried at the same level across or around a building. It is usually made of a flat member and a moulding.
Belt Drive
A belt used to transmit power between two shafts.
Belt Noise
There are many different mechanisms by which drive belts generate noise.
Belville Washer
Often used on smaller angular contact arrangements to provide a preload.
Bench Dogs
Pegs which go into holes in the top of a workbench that work with a vise to hold wide material.
Bench Grinder
A small grinding machine for shaping and sharpening the cutting edges of tools.
Bench Lathe
A small lathe mounted on a bench or table.
Bench Vice
A device attached to a bench with two jaws that can be moved parallel to each other and used to hold a workpiece.
Bench Work
Work done primarily at a bench with hand tools.
Bend Radius
The inside radius of a bent section.
Bend Test
Various tests which are used to ascertain the toughness and ductility of a metal product, in which the material is bent around its axis and or around an outside radius.
The ratio of the curvatures of a lens′s two refracting surfaces.
Bending Mode
Mode of vibration in which cross sections of a beam, shaft or structure undergo translation and rotation. Type of translational mode usually found in slender structures with evenly distributed mass and stiffness.
Bending Moments
Internal forces on a structural element that cause the element to bend and thus create internal compression on one side of the element and internal tension on the other.
Bending Stress
Stress on the cross-sectional area of a beam due to the bending moment of the beam under load.
Beneden, Eduard van
Cytologist who demonstrated the constance of chromosome numbers for the species, the reduction of their number during maturation of germ cells, and the restoration of the double number at fertilization.
Bent Nose Pliers
Pliers with bent jaws.


A colourless to yellow liquid with an almon like odour. Also known as Benzoic Aldehyde, Almond Artificial Essential Oil, Benzenecarbonal, Benzene Carboxaldehyde and Oil of Bitter Almond.

An aromatic hydrocarbon used in the manufacture of many organic compounds.
Benzene Carboxaldehyde
Alternative name for Benzaldehyde.
Alternative name for Benzaldehyde.
Benzoic Acid


Used as a fruit preservative. At room temperature it is a colourless solid forming glistening needles and plates, sublimes easily and is volatile in steam.

Benzoic Aldehyde
Alternative name for Benzaldehyde.


An organic compound consisting of an ethylene bridge flanked by phenyl groups and with a hydroxyl and a ketone functional group. It comes as off-white crystals, with a light camphor odor.

Chemical formula of Beryllium Oxide.
Element with an atomic number of 97.
Berlin Eye
Refers to the eye of a leaf spring when the eye is upturned.
Bernoulli, Daniel
Showed that the total energy in a steadily flowing fluid system is a constant along the flow path.
Bernoulli Trial
An experiment with only two possible outcomes, such as success or failure, heads or tails, or good or bad.
Bernoulli′s Principle
The pressure in a fluid decreases as its velocity increases.
Alternative name for Beryllium Oxide.
Beryllia Ceramic
Alternative name for Beryllium Oxide.
Beryllium is a light and lustrous metal that is resistant to attack by air or water, even at elevated temperatures
Beryllium Bromide


Hygroscopic and dissolves readily in water.

Beryllium Chloride


White crystalline substance that reacts vigorously and exothermically with water with the evolution of acidic, steamy hydrogen chloride gas. It attacks many metals in presence of water.

Beryllium Copper
Heat treatable copper-beryllium alloy of high strength and hardness. Used for making springs and non-sparking tools.
Beryllium Fluoride


A crystalline solid, the principal precursor for the manufacture of beryllium metal.

Beryllium Hydroxide


A white solid. One of only a few amphoteric metal hydroxides.

Beryllium Iodide


Colourless needle-like crystals that are very hygroscopic and reacts violently with water, forming hydroiodic acid.

Beryllium Nitride


A common component of refractory ceramics.

Beryllium Oxide


White crystalline oxide that when sintered is very stable and has ceramic characteristics.

Beryllium Telluride


A crystalline solid that is a semiconductor with a large energy gap of around 3 eV.

Berzelius, Jons Jakobs
Swedish physician and chemist. Discovered cerium, selenium, lithium, silicon, titanium and thorium; coined the terms "isomer" and "isomerism".
Bessemer, Henry
English engineer and inventor who developed an inexpensive steel-making process.
A letter of the Greek alphabet.
Beta Decay
Radioactive process in which a beta particle is emitted from the nucleus of an atom.
Beta Distribution
A distribution used for continuous random variables which are constrained to lie between 0 and 1.
Beta Particle
An electron emitted by a radioactive nucleus.
Beta Ray
A stream of beta particles.
Beta Risk
The probability of not rejecting a null hypothesis when it is false. It is the probability of making a Type II error.
Beta Stirling Engine
A stirling enging with a single power piston arranged coaxially with a displacer piston.
The current gain in a grounded-emitter transistor amplifier.
An accelerator in which electrons are accelerated to high energies by an electric field produced by a changing magnetic field.
Chemical formula of Beryllium Telluride.
An accelerator in which protons are raised to energies of several billion electron-volts by modulating the frequency of the accelerating voltage.
Any surface that is not at right angles to another surface. Also, the name given a tool used for measuring, laying out, or checking the accuracy of work machined at an angle or bevel.
Bevel Angle
The angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member.
Bevel Edge Chisel
A woodworking tool with the side edges beveled used for general cutting.
Bevel Gear
Conical shaped gears, the angle between the input and output shaft is anything except 0 or 180°.
Beverage Antenna
A horizontal, long-wire antenna designed for reception and transmission of low-frequency, vertically polarized ground waves.