Abbreviation of Programmable Logic Array.
Place Effect
The theory that pitch perception is related to the pattern of excitation on the basilar membrane of the cochlea.
Place Value
Within a number, each digit is given a place value depending on it′s location within the number.
Plain Bearing
A relatively simple and inexpensive bearing typically made of two parts. A rotary plain bearing can be just a shaft running through a hole.
Plain Cutter
A milling cutter with cutting teeth on the periphery only.
Plain Screwdriver
A screwdriver with a flat tip designed to fit in the simple slot on the head of a screw.
Plan Position Indicator
A conventional radar display of the location of targets on a horizontal plane.
Planar Power Transformer
A stacked layer design transformer.
Planar Tube
An electron tube, constructed with parallel electrodes and a ceramic envelope, that is used at uhf frequencies.
Planck, Max
German physicist who is regarded as the founder of the quantum theory, for which he received the Nobel Prize in Physics in 1918.
Planck Radiation Law
A law which described blackbody radiation better than its predecessor, thus resolving the ultraviolet catastrophe.
Plancks Constant
h = 6.62620x10-34Js
A two-dimensional group of points that goes on infinitely in all directions; made up of infinite lines.
Plane Angle
The plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius is 1 radian.
Plane of Polarization
The plane, with respect to the earth, in which the E field propagates.
Plane Section
The intersection of a figure with a plane.
Plane Wave
Wave in which the wavefronts are everywhere parallel planes normal to the direction of propagation.
Plane Wood
A North American wood that resembles beech, durable in water but not in air.

A spherical ball of rock and/or gas that orbits a star.
Planetary Nebula
A bright cloud of dust and gas surrounding an old star, namely a red giant.
The shape or form of an object as seen from above, as in a plan view.
Machining operation that creates flat surfaces.
Aquatic organisms that drift or swim weakly.
The fourth state of matter in which one or more electrons have been stripped from the atoms forming an ion gas.
Plasma Discharge
Low-density, low-temperature plasma discharge such as in a fluorescent tube.
Plasma Frequency
The natural collective oscillation frequency of a charge species in a plasma, in the absence of a magnetic field.
Plasma Membrane
The exterior membrane surrounding the cytoplasm of a cell.
Plasma Proteins
The proteins present in blood plasma.
Plasma Wave
A disturbance of a plasma away from equilibrium, involving oscillations of the plasma′s constituent particles and/or the electromagnetic field.
Plaster of Paris
Partly dehydrated gypsum.
A board used in large sheets as a backing or as a substitute for plaster in walls and consisting of fiberboard, paper, or felt, bonded to a hardened gypsum core.
A solid material in the primary ingredient of which is an organic polymer of high molecular weight.
Plastic Deformation
Deformation that is permanent or nonrecoverable after release of the applied load.
Plastic Flow
Alternate name for Plastic Deformation.
Plastic Strain
Alternate name for Plastic Deformation.
Plastic Strain Ratio
Ratio of the true width strain to the true thickness strain.
Modelling Clay.
The inverse of elasticity. A material that tends to stay in the shape or size to which it is deformed has high plasticity.
Plasticity Number
Index of the compressibility of rubber at elevated temperatures.
A low molecular weight polymer additive that enhances flexibility and workability and reduces stiffness and brittleness.
In plants, a self-replicating organelle; may differentiate into a chloroplast.
One of the electrodes in a storage battery or A planar body whose thickness is small compared with its other dimensions.
Plate Modulator
An electron-tube modulator in which the modulating voltage is applied to the plate circuit of the tube.
Plate Resistance
The plate voltage change divided by the resultant plate current change in a vacuum tube, all other conditions being fixed.
Plate Techtonics
Motion of the plates that make up the surface of the Earth.
Small, enucleated cells that initiate blood clotting which arise from megakaryocytes in the bone marrow.
Forming an adherent layer of metal on an object; often used as a shop term for electroplating.
A lustrous, malleable and ductile metallic element.
A Greek philosopher, pupil of Socrates and Aristotle′s teacher.
Platonic Year
The period of one complete cycle of the equinoxes around the ecliptic, about 25800 years.
A distribution that is less peaked than a normal distribution.
Abbreviation for Programmable Logic Device.
Pleated Filter
A filter element whose medium consists of a series of uniform folds and has the geometric form of a cylinder, cone, disc, plate, etc.
The geological epoch covering about 1.64 million years ago to 10000 years ago.
Air compartment connected to a duct or ducts.
A gripping tool with two hinged arms and serrated jaws.
Plinian Eruption
An explosive eruption in which a steady, turbulent stream of fragmented magma and magmatic gases is released at a high velocity from a vent.
The geological period covering about 5.2 million years ago to 1.64 million years ago.
Exactly vertical.
The natural allotropic form of carbon.
Latin for lead, hence the symbol Pb.
The long piston of a single-acting pump, such as a fuel-injection pump.
The symbol: +
The outermost planet in our solar system and it′s double Charon.
Igneous rock bodies that form at great depth.
A product of the radioactive decay of neptunium.
Thin sheets of wood glued together with the grains running in different directions to improve the strength of the resultant board.