Board Foot
A unit of lumber volume, a rectangular solid nominally 12" x 12" x 1". The equivalent of a board 1-foot square and 1 inch thick.
A small craft that floats on water.
The rear portion of an elongated body, having decreasing cross-sectional area toward the rear.
Bobbiere Metal
A brass made with 66% copper and 34% zinc.
Bode Plot
A plot of the frequency response function that includes log magnitude versus frequency plus phase versus frequency.
Body Centred Cubic
About 15% of elements crystallize with a body centred cubic structure.
Body Force
An external force acting throughout the mass of a body.
Body Hammer
A hammer with a large flat pounding surface for removing dents.
Body Mass Index
A measure of fatness used in medicine and health.
Abbreviation of Barrel of Oil Equivalent.
Bohman Window
A weighting that is applied in the time domain to reduce leakage within a Fourier Transform analysis.
Bohr Atom
A model of the atom that explains emission and absorption of radiation as transitions between stationary electronic states in which the electron orbits the nucleus at a definite distance.
Bohr Magneton
b = 9.27x10-24 Am2
Bohr, Niels
While at Copenhagen University, Bohr, in 1922, won the Nobel Prize in Physics "for his services in the investigation of the structure of atoms and of the radiation emanating from them."
Bohr Radius
a0 = 5.291772x10-11 m
A device for generating steam for power, processing, or heating purposes or for producing hot water for heating purposes or hot water supply.
Boiler Dome
A raised location on the top of the main boiler drum, providing a high point from which to collect dry steam, reducing the risk of priming.
Boiler Suit
Heavy-duty one-piece protective clothing.
The rapid vapourization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure.
Boiling Point
The temperature at which the vapour pressure of a liquid is equal to the external pressure on the liquid.
Boiling Point Elevation
The boiling point of a solution is higher than the boiling point of the pure solvent.
Boiling Range
For a mixture of substances, such as a petroleum fraction, the temperature interval between the initial and final boiling points.
A brilliant meteor, especially one which explodes, a detonating fireball.
Bollman, Wendel
Bridge Design Engineer who patented his unique suspension truss form and became the pioneer builder of iron railroad bridges in America.
A device for measuring minute amounts of radiant energy.
A cylindrical threaded fastener.
Bolt Bound
The situation whereby a part cannot be moved in the desired direction because of mounting hole restrictions.
Bolt Cutters
Cutters with strong jaws and long handles designed for manually cutting through thick steel bolts.
Bolt of Cloth
A standard unit of length used in the fabric industry.
Bolted Fault
A short circuit condition that assumes zero impedance exists at the point of the fault.
Bolted Joint
A joint formed between two or more pieces of material with the application of a nut and bolt.
Boltzmann, Ludwig Eduard
Austrian physicist famous for his contributions in the fields of statistical mechanics and statistical thermodynamics.
Boltzmann′s Constant
Constant named after Stefan Boltzmann. Used in the determination of energy radiation from bodies.
Bomb Calorimeter
A bomb calorimeter measures the enthalpy of combustion.
Bond Energy
The energy required to break a given chemical bond.
Bond Enthalpy
Enthalpy change per mole when a bond is broken in the gas phase for a particular substance.
Bond Length
The average distance between the nuclei of two bonded atoms in a stable molecule.
Bond Order
In Lewis structures, the number of electron pairs shared by two atoms.
Bond Strength
Some measure of how difficult it is to break a chemical bond, for example, a bond energy or a bond enthalpy.
Bondi, Sir Hermann
Astrophysicist who helped formulate the steady-state theory of the universe - which said it has always existed.
Bonding Energy
The energy required to separate two atoms that are chemically bonded to each other.
Bonding Wires
Fine wires connecting the bonding pads of the chip to the external leads of the package.
Primarily based on phosphate and carbonate.
Bone Black
An impure animal charcoal prepared from bones and blood.
Successive layers of veneer are arranged side by side to resemble a mirror image of each other.
Lists all the Books referenced in the Encyclopaedia
Boole, George
British mathematician who devised a new form of algebra that represented logical expressions in a mathematical form now known as Boolean Algebra.
Pertaining to the operations of formal logic.
Boolean Algebra
A system of logic dealing with on-off circuit elements associated by such operators as the AND, OR, NAND, NOR, and NOT functions.
Boolean Operation
Command that allows the addition, subtraction or intersection of solid objects in CAD.
Listening term, refers to an excessive bass response that has a peak(s) in it.
Boost Pressure
The increase above atmospheric pressure produced inside the intake manifold by a forced-induction system such as a turbocharger or supercharger.
Boot Up
Literally, the process of loading up the operating system and getting the computer ready for use.
Bootstrap Protocol
Protocol that allows an Internet node to discover certain startup information, such as its IP address.
The interior diameter of a cylinder.
Bore and Stroke
The bore and stroke of the piston sets the swept volume.
Borelli, Giovanni
Italian physiologist, philosopher, mathematician, and disciple of Galileo who applied the latter’s principles of physics to biology, thus suggesting an experimental approach to the science.
Enlarging a hole that already has been drilled or cored.
Boring Bar
Essentially a cantilever beam that holds one or more cutting tools in position during a boring operation.
Boring Machine
Similar to a turning machine except that the cutting tool, rather than the workpiece, rotates to perform internal cuts.
Born, Max
Won the Nobel Prize in Physics for his fundamental research in quantum mechanics.
Boron is a non-metallic element which occurs in several allotropes.
Boron Monoxide


Chemical compound of boron and oxygen.

Boron Nitride


Excellent thermal and chemical stability, boron nitride ceramics are traditionally used as parts of high-temperature equipment.

Boron Suboxide


Due to its short interatomic bond lengths and strongly covalent character, it displays a range of outstanding physical and chemical properties such as great hardness, low mass density, high thermal conductivity, high chemical inertness, and excellent wear resistance.

Boron Trioxide


White glassy solid almost always found as the vitreous form; however, it can be crystallized after extensive annealing.

Bose-Einstein Statistics
Quantum statistics for particles not obeying the exclusion principle.
Particles which do not obey the Pauli exclusion principle, for example, photons.
A projection or an enlarged section of a casting through which a hole may be machined.
Bossing Mallet
A hammer with a pear-shaped wooden head used for shaping and stretching metal over a sandbag or wooden block.
A unit of volume.
The flavor of the fifth quark.
Bottom Ash
Incombustible matter resulting from combustion that does not leave as fly ash.
Bottom Dead Centre
The position of the crank when the piston is in its closest position to the crankshaft, in its farthest position from the cylinder head. Abbreviated bdc.
Bottom End
The collective term for the internal combustion engine block and the components it houses.
A transistor in the fully conducting state.
Bouch, Sir Thomas
Railway Engineer who invented caissons and train ferries.
Bouguer Law
A relationship describing the rate of decrease of flux density of a plane-parallel beam of monochromatic radiation as it penetrates a medium which both scatters and absorbs at that wavelength.
A sausage-shaped, synthetic single-crystal mass grown in a special furnace, pulled and turned at a rate necessary to maintain the single-crystal structure during growth.
A term which is used to describe the oscillations of a rigid body, for example, the sprung and unsprung masses of a vehicle, that consists primarily of vertical displacement.
Bound of a Function
A curve that encloses the major peaks of the envelope of a function.
Bound State
This is a state in which a particle is confined within a composite system.
Boundary Element Method
A mathematical formulation used to predict acoustic parameters such as pressure and power. This technique may be applied to interior and exterior acoustic problems.
Boundary Layer
The portion of a fluid flowing past a body that is in the immediate vicinity of the body.
Boundary Lubrication
Occurs when the load-bearing surfaces come into contact.
Boundary Microphone
A type of microphone that detects sound pressure level changes at a boundary of the acoustic space in order to reduce interference between direct and reflected sound.
Bourdon Tube
Thin-walled tube of elastic metal flattened and bent into circular shape, which tends to straighten as pressure inside is increased.
Bow Saw
Ideal for pruning, landscaping work and sawing firewood.
Bow Shock
The shock wave caused by the edge our Solar System travelling through deep space.
Bowstring Truss
Structural framework for supporting loads over long spans.
A surface made up of rectangles; a rectangular parallelpided.
Box Annealing
Annealing a metal or alloy in a sealed container under conditions that minimize oxidation.
Box Plot
A graphic method that shows the distribution of a set of data by using the median, quartiles, and the extremes of the data set.
Box Spanner
A hollow tube with a socket at each end and two holes through which a bar can be inserted to turn the tube.
Box Wrench
American name for a ring spanner.
The operation of continuing a fillet weld around a corner of a member as an extension of the principal weld.
Very compact hard wood suitable for machining small parts from.
Boyle, Robert
Known for that scientific law named after him.
Boyles Gas Law
For a fixed mass of gas at constant temperature the product of pressure and volume is constant.