mA
Milliampere (one-thousandth of an ampere)

Magnet Wire
Insulated wire used in the windings of motors, transformers, and other electromagnetic devices

MAP
Manufacturing Automation Protocol. The OSI profile championed by General Motors Corporation to provide interconnectivity between plant hosts, general managers and cell controllers over a broadband token-passing bus network

Marker Tape
A tape laid parallel to the conductors under the sheath in a cable, imprinted with the manfacturer's name and the specification to which the cable is made

Marker Thread
A colored thread laid parallel and adjacent to the strand in an insulated conductor which identifies the manufacturer and sometimes the specification to which the wire is made

Mastic
A meltable coating used on the inside of some shrink products which when heated flows to help create a waterproof seal

MATV
Master Antenna Television System. A combination of components providing multiple television receiver operations from one antenna or group of antennas

Maximum Cable Diameter
The largest cable diameter that a high-voltage cable termination is designed to accommodate

Minimum Cable Diameter
The smallest cable diameter that a high-voltage cable termination is designed to accommodate

Maximum Design Voltage
The maximum voltage at which a high-voltage cable termination is designed to operate continuously under normal conditions

MC
(1) Main cross-connect
(2) A UL cable type (metal clad)

Mechanical Water Absorption
A check of how much water will be absorbed by material in warm water for seven days (mg/sq. in surface)

Medium Frequency
The band of frequencies between 300 and 3,000 kilohertz

Medium-Hard Drawn Wire
As applied to copper wire, having tensile strength less than the minumum for hard-drawn wire, but greater than the maximum strength for soft wire

Medium Voltage
A class of nominal power system voltage ratings from 2 kV up to 69 kV

Mega
Prefix meaning million

Megahertz (MHz)
One million cycles per second

Megger
A special ohmmeter for measuring very high resistance. Primarily used for checking the insulation resistance of cables, however, it is also useful for equipment leakage tests

Melt Index
The extrusion rate of a material through a specified orifice under special conditions

Member
A group of wires stranded together which is in turn stranded into a multi-membered conductor

Messenger Wire
A metallic supporting member either solid or stranded which may also perform the function of a conductor

MFD
Microfarad (one-millionth of a farad). Obsolete abbreviation

MFT
Abbreviation for 1,000 feet

MG
Glass reinforced mica tape insulated cable with an overall sheath of woven glass yarn impregnated with a flame, heat and moisture resistant finish. 450ºC, 600V appliance wire

MHO
The unit of conductivity. The reciprocal of an ohm

MHz
Megahertz (one million cycles per second)

MI
A UL cable type. One or more conductors insulated with highly compressed refractory minerals and enclosed in a liquidtight and gas-tight metallic tube sheathing

MICA
A transparent silicate which separates into layers and has high insulation resistance, high dielectric strength, and high heat resistance

Micro
Prefix meaning one-millionth

Microbending Loss
A signal loss due to small geometrical irregularities along the core-cladding interface of optical fibers

Microfarad
One-millionth of a farad (abbreviated µf)

Micromicrofarad
One-millionth of a microfarad (abbreviated µµf). Also, a picofarad (pf)

Microphone Cable
A very flexible, usually shielded cable used for audio signals

Microphonics
Noise caused by mechanical movement of a system component. In a single conductor microphone cable, for example, microphonics can be caused by the shield rubbing against the dielectric as the cable is flexed

Microwave
A short (usually less than 30 cm) electrical wave

Mid-Split
A broadband cable system in which the cable bandwidth is divided between transmit and receive frequencies. The bandwidth utilized to send toward the head-end (reverse direction) is approximately 5 MHz to 100 MHz, and the bandwidth utilized to send away from the head end (forward direction) is approximately 160 MHz to 300 MHz. The guard band between the forward and reverse directions (100 MHz to 160 MHz) provides isolation from interference

mil
A unit of length equal to one-thousandth of an inch

MIL
Military specification

MIL-C-17
A military specification covering many coaxial cables

MIL-W-16878
A military specification covering various wires intended for internal wiring of electric and electronic equipment

MIL-W-22759
A military specification for fluorocarbon insulated copper and copper alloy wire

Milli
Prefix meaning one-thousandth

MIPS
Millions of Instructions Per Second

Modulation
Systematic changing of properties, eg amplification, frequency, phase of an analog signal to encode and convey (typically digital) information

Modulus of Elasticity
The ratio of stress (force) to strain (deformation) in a material that is elastically deformed

Moisture Absorption
The amount of moisture, in percentage, that a material will absorb under specified conditions

Moisture Resistance
The ability of a material to resist absorbing moisture from the air or when immersed in water

Molded Plug
A connector molded on either end of a cord or cable

Mono Filament
A single strand filament as opposed to a braided or twisted filament

Monomer
The basic chemical unit used in building a polymer

Motor Lead Wire
Wire which connects to the fragile magnet wire found in coils, transformers, and stator or field windings

MPF
Mine Power Feeder cables. Usually rated 5, 8 or 15kV

MSHA
Mine Safety and Health Administration. The Federal enforcement agency for employee safety in mines and mills. Formerly known as MESA, Bureau of mines. MSHA regulations appear in CFR Title 30, Chapter 1

MTW
Machine Tool Wire. Thermoplastic insulated, 90ºC to 105º, 600V. A UL cable type

Multicast
The ability to broadcast messages to one node or a select group of nodes

Multidrop
See Multipoint Circuit

Multimode
Optical fiber which allows more than one mode of light to propagate

Multiple-Conductor Cable
A combination of two or more conductors cabled together and insulated from one to another and from sheath or armor where used

Multiple-Conductor Concentric Cable
An insulated central conductor with one or more tubular stranded conductors laid over it concentrically and insulated from one another

Multiplex
The use of a common physical channel in order to make two or more logical channels, either by the splitting of the frequency band (frequency-division multiplex), or by utilizing this common channel at different points in time (time-division multiplex)

Multiplexer
Equipment that permits simultaneous transmission of multiple signals over one physical circuit

Multipoint Circuit
A single line connecting three or more stations

Murray Loop Test
A method used to localize cable faults

Mutual Capacitance
Capacitance between two conductors in a cable

Mux
Multiplex. To transmit two or more signals over a single channel

mV
Millivolt (one-thousandth of a volt)

MV
Medium voltage cables. Usually rated 5-35 kV

mW
Milliwatt (one-thousandth of a watt)

MYLAR®
DuPont's trademark for polyethylene terephthalate (polyester) film

Marine Shipboard Cable
Impervious sheathed armoured or non-armoured cable constructed in accordance with UL 1309/CSA C22.2 No. 245, except that an overall impervious sheath is required over the armoured construction, and listed as "Shipboard Cable, Marine" by a Nationally Recognised Testing Laboratory (NRTL)