The electronic manufacturing industry can be filled with complex concepts, numerous acronyms, and a plethora of terms that can sometimes be difficult to understand. In this article, we have compiled some of the complex terms used in electronic manufacturing services. This abbreviated glossary is intended to assist individuals in OEM and electronic contract manufacturing industries and is comprised of manufacturing, engineering, and related technical terms..

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z



Assembly Language

A computer language made up of brief expressions that an assembler program can translate into a machine language.


The reduction in the amplitude of a signal due to losses in the media through which it is transmitted. The unit of measure is decibels (dB).

Azeotropic Mixture (Azeotrope)

A liquid mixture of two or more substances that behaves like a single substance. The vapor produced by partial vaporization of the liquid has the same composition as the liquid.


Binomial Distribution

A discrete probability distribution that, with certain assumptions, describes the variation of an attribute (proportion).


A general name for any substance that kills or inhibits the growth of microorganisms.



The property of a system of conductors and dielectrics that allows the storage of electricity when a potential difference exists between the conductors.

Color Temperature

A measure of the energy distribution over the visible spectral range of a light source with a continuous spectrum expressed in degrees Kelvin (K).

Confidence Interval

The determination, with a specified degree of confidence, as to whether or not a particular characteristic is within ascertained limits of a population.



A separation between plies within a base material, between a base material and a conductive foil, or any other planar separation with a printed board.

Dielectric Constant

The ratio of the capacitance of a configuration of electrodes with a specific material as the dielectric between them to the capacitance of the same electrode configuration with a vacuum or air as the dielectric.


The existence of a substance in two different crystalline forms.

Dipole Moment

An assemblage of atoms or subatomic particles, separated by a finite distance, that have equal electric charges of opposite sign.



The electro-deposition of a metal coating on a conductive object. The object to be plated is placed in an electrolyte and connected to one terminal of a direct current (DC) voltage source. The metal to be deposited is similarly immersed and connected to the other terminal.


Solder that has a very short transition from liquid to solid, an optimal mix with no plastic state.


The enrichment of either fresh or salt water by a chemical element or compound.


Fishbone Diagram

A problem-solving tool that uses a graphic description of various process elements in order to analyze potential sources of process variation. Also known as a Cause-and-Effect Diagram.


The combination or aggregation of suspended solid particles in such a way that they form small clumps or tufts that resemble wool.


Galvanic Corrosion

Corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes.

Gaussian Distribution

A mathematically defined continuous distribution of values that has a bell shape that is perfectly symmetrical about a mean value.  Also known as Normal Distribution.

Gerber File

Data file used to control a photo-plotter. Named after the Gerber Scientific Co., who made the original vector photo-plotter.

Glass Transition Temperature

The temperature at which an amorphous polymer, or the amorphous regions in a partially crystalline polymer, changes from being in a hard and relatively brittle condition to being in a viscous or rubbery condition.



A mechanical device that is made of a high thermal-conductivity and low specific-heat material that dissipates heat generated by a component or assembly.


A cyclic or ring structure, often in the shape of a pentagon, in which one or more of the atoms in the ring is an element other than carbon.

Hipot Test

A method in which the unit under test is subjected to a high alternating current (ac) voltage.

Homologous Series

A series of organic compounds in which each successive member has one more CH2 group in its molecule than the preceding member.


A polymer derived from a single monomer with the aid of initiators that act in the manner of catalysts.


Ion Exchange

A reversible chemical reaction between a solid and a fluid by means of which ions are interchanged from one substance to another.


Jumper Wire

A discrete electrical connection that is part of the original design and is used to bridge portions of the basic conductive pattern formed on a printed board.



A general term that encompasses both keying slots and polarizing slots.


Luminous Flux

A measure of flow of visible light energy past any given point in space.


Manhattan Distance

The orthogonal distance between two points.

Mother Board

A printed board assembly that is used for interconnecting arrays of plug-in electronic modules.


Nail Heading

The flared condition of copper on an inner conductive layer of a multilayer printed board that is caused by hole drilling.


Original equipment manufacturer (OEM)

The company behind the “brand name” of a product that traditionally designed, manufactured, marketed, and provided customer support for their products. Increasingly, one or more of these activities are being outsourced to EMS companies. Examples of OEMs include IBM, Hewlett-Packard, Cisco, Sun Microsystems, Sony, Fujitsu, Siemens, Philips, and many others.


Pareto Analysis

A problem-solving technique whereby all potential problem areas or sources of variation are ranked according to their contribution to the end result.


The formation of an insulating layer to protect a surface from contaminants, moisture, and particulate matter.


The measurement of the effect of the intensity and energy of visible light on the human eye.


A material that is sensitive to portions of the light spectrum and that, when properly exposed can mask portions of a base metal with a high degree of integrity.

Plastic Deformation

Deformation that does, or will, remain permanent after removal of the load that caused it.

Poisson Distribution

A discrete probability distribution for attributes data that is particularly applicable when there are many opportunities for the occurrence of an event but a low probability on each trial.

Propagation Delay

The time required for an electronic signal to travel along a transmission line, or the time required for a logic device to perform its function and to present a signal at its output.


Quality-Conformance Test Circuitry

A portion of a printed board panel that contains a complete set of test coupons that are used to determine the acceptability of the board(s) on the panel. soluble flux.


Reference Designator

The name of components on a printed circuit by convention beginning with one or two letters followed by a numeric value. The letter designates the class of component; eg. “Q” is commonly used as a prefix for transistors. Reference designators appear as usually white or yellow epoxy ink (the “silkscreen”) on a circuit board. They are placed close to their respective components but not underneath them. So that they are visible on the assembled board.

Regression Analysis

The use of statistics to investigate and model the relationships between parameters and results.


Sequentially Laminated Multilayer Printed Board

A multilayer printed board that is formed by laminating together through-hole plated double-sided or multilayer boards. (Thus, some of its conductive layers are interconnected with blind or buried vias.)

Stress Corrosion Cracking

Spontaneous cracking produced by the combined action of corrosion and residual or applied static stress.



Formerly Bellcore, telecommunication (telephone) industry standards


A property of a substance, e.g., an adhesive system, that allows it to get thinner upon agitation and thicker upon subsequent rest.

Type I Error

The rejection of a hypothesis that is true.

Type II Error

The accepting of a hypothesis that is false.


Ultrasonic Cleaning

Immersion cleaning that is done by passing high-frequency sound waves through a cleaning medium to cause micro-agitation.

UL – Underwriter’s Laboratories, Inc.

A corporation supported by some underwriters for establishing safety standards on types of equipment or components. Their logo shows applicable UL certification.


Voltage Plane

A conductor layer, or portion thereof, that serves as a common voltage source at other than ground potential for an electrical circuit, shielding, or heat sinking.  Also known as a “Ground Plane” and “Signal Plane”.



A tube used to transmit microwave-frequency electromagnetic wave energy.



The horizontal or left-to-right direction in a two-dimensional system of coordinates. (This axis is perpendicular to the Y-axis.)



The vertical or bottom-to-top direction in a two-dimensional system of coordinates.



The Axis perpendicular to the plane formed by the X and Y datum reference. This axis usually represents the thickness of the boards.