| M | Million; Mega |
| MA | Mechanical Advantage |
| MAC | Multiplexed Analogue Components; MacPaint image format; Maximum Allowable Concentration; Medium Access Control (DVB-RCT); Message Authentication Code |
| MACT | Maximum Achievable Control Technology |
| MALDI | Matrix-Assisted Laser Desorption and Ionization |
| MAM | Media Asset Management |
| MAN | Metropolitan Area Network |
| MAP | Manufacturing Automation Protocol |
| MAS | Microbeam Analysis Society |
| MATS | MAterial Transport Segment |
| MAWP | Maximum Allowable Working Pressure |
| MB | Machine Batch; Mega Bytes |
| MBC | Machine Bath Collection |
| MBE | Molecular Beam Epitaxy |
| MBMS | Molecular Beam Mass Spectrometry |
| MBPC | Model-Based Process Control |
| MBTC | Model-Based Temperature Control |
| MBX | Message Bus eXchange |
| MCA | Measurement Capability Analysis |
| MCAD | Mechanical CAD |
| MCAE | Mechanical CAE |
| MCBA | Mean Cycles Between Assists |
| MCBF | Mean Cycles Between Failures |
| MCBI | Mean Cycles Between Interrupts |
| MCBSE | Mean Cycles Between Scrap Event |
| MCD | Magnetic Circular Dichroism; Millicandela |
| MCM | MultiChip Module; Manufacturing Cycle Management |
| MCM-C | MCM-Ceramic |
| MCM-D | MCM-Dielectric |
| MCM-P | MCM-Plastic |
| MCNS | Multimedia Cable Network System Partners |
| MCP | MultiChip Package |
| MCS | Material Control System |
| MCT | Mercury Cadmium Telluride detector; MOS Controlled Thyristor |
| MCTF | Motion Compensated Temporal Filtering |
| MCU | Microprocessor Control Unit; Mobile Calibration Unit |
| MCVD | Metal Chemical Vapor Deposition |
| Md | Mendelevium |
| MD | Molecular Dynamics; Mini Disk |
| MDA | MethyleneDiAniline |
| MD-MOS | Multi-Drain Metal-Oxide Semiconductor |
| MDL | Minimum Detection Limit; Master Deliverables List; Maximum Doping Limit |
| MDQ | Market Driven Quality |
| MDQW | Modulation Doped Quantum Well |
| MDRAM | Multibank DRAM |
| MDS | Modify Device Status |
| MDU | Modular Dispensing Unit |
| MEBS | Medium Energy Backscattering Spectrometry |
| MED | Modeling for Equipment Design |
| MEE | Migration Enhanced Epitaxy |
| mega | 1.00E+6 (1,000,000/1; symbolized by the prefix M) |
| MEIS | Medium Energy Ion Scattering |
| MEK | Methyl-ethyl ketone |
| MELF | Metal Electrode Face (discrete leadless component) |
| MEM | Micro Electro Mechanical; Manufacturing Enterprise Model; Manufacturing Equipment Monitor |
| MEMS | Micro Electro Mechanical Systems |
| MMD | Microlithographic Mask Development program |
| MMDS | Multichannel Multipoint Distribution Service |
| MMIC | Monolithic microwave integrated circuit |
| MMM | Material movement management; Magnetism and Magnetic Materials |
| MMMC | Machine material movement component |
| MMMS | Material Movement Management Standard |
| MMO | Multimodel optimization |
| MMOS | Modified MOS |
| MMS | Windows Media Technology's transport protocol; Multimedia Messaging Service |
| MMST | Microelectronics Manufacturing Science and Technology |
| MMU | Memory Management Unit |
| mmwave | Millimeter Wave |
| Mn | Manganese |
| MNDO | Modified Neglect of Diatomic Overlap |
| MNOS | Metal-nitride-oxide semiconductor |
| MNS | Metal-nitride semiconductor |
| Mo | Molybdenum |
| MO | Metal-organic |
| MOCVD | MetalOrganic Chemical Vapor Deposition |
| MOD | Magneto Optical Disc |
| MODEM | MOdulator/DEModulator |
| MODFET | MOdulation Doped Field Effect Transistor |
| MOMBE | Metal-Organic Molecular Beam Epitaxy |
| MONET | Multi-wavelength Optical NETwork |
| MOP | Modify Operating Procedures |
| MORIE | MetalOrganic Reactive Ion Etching |
| MOS | Metal-Oxide Semiconductor |
| MOS-C | Metal Oxide Semiconductor Capacitor |
| MOSFET | Metal Oxide Semiconductor FET |
| MOT | Magneto Optical Trap |
| MOVPE | Metal-Organic Vapor-Phase Epitaxy |
| MP | Multi Phonon; Melting point; Massively parallel |
| MPA | Microwave Power Absorbtion |
| MPEG | Motion Picture Experts Group (aka MPG) |
| MPF | Mobile Payment Forum |
| MPL | Magneto Photo Luminescence; Multilevel pass transistor logic |
| MPLS | Multiprotocol Label Switching |
| MP-OES | Multi-point optical emission spectroscopy |
| MPP | Multiphase printing |
| MPRES | Modular plasma reactor simulator |
| MPSA | Mobile Payment Services Association |
| MPTS | Multi-Program Transport Stream |
| MPU | Microprocessor unit |
| MPW | Multi-Product Wafer |
| MPX | Multiplex |
| MQ-NMR | Multiple Quantum NMR |
| MQW | Multiple Quatum Well |
| MR | Magnetic resonance; Magneto resistive |
| MRI | Magnetic resonance imaginery |
| MRP | Materials requirements planning; Manufacturing resource planning |
| MRS | Materials Research Society |
| MS | Mass spectrometry; Mass spectrometer; Mass spectroscopy |
| MSA | Microscopy Society of America |
| MSB | Most significant bit |
| MSDC | Multistage Depressed Collector |
| MSDS | Material Safety Data Sheet |
| MSEM | Metrology Specific Equipment Model |
| MSG | Management Steering Group |
| MSHA | Mine Safety and Health Administration |
| MSI | Medium-scale integration; manufacturing support item |
| MSID | Mass spectrometer lead detector |
| MSL | Modify system logging |
| MSLD | Mass spectrometer leak detector |
| MSM | Metal-Semiconductor-Metal |
| MSO | Multiple Systems Operator |
| MSP | Microsoft Paint image format |
| MSS | Modify system state; Modulation semiconductor structure |
| MST | Micro System Technology |
| MSTAB | Manufacturing Systems Technical Advisory Board |
| MTBA | Mean time between assists |
| MTBAP | Mean (productive) time between assists |
| MTBF | Mean Time Between Failures |
| MTBFP | Mean (Productive) Time Between Failures |
| MTBI | Mean Time Between Interrupt; Mean Time Between Incident |
| MTOL | Mean Time Off Line; Mean Time On Line |
| MTS | Material Tracking Standard |
| MTSC | Memory Time Switch CMOS |
| MTSL | Memory Time Switch Large |
| MTSS | Memory Time Switch Small |
| MTT | Mail TrusT |
| MTTA | Mean Time To Assist |
| MTTC | Mean Time To Correct |
| MTTF | Mean Time To Failure |
| MTTR | Mean Time To Repair |
| MUART | Multiple UART; Multifunctions Universal Asynchronous Receiver Transmitter |
| MUDEM | MUltiplexer/DEMultiplexer |
| MUL | Modify User Login |
| MUNICH | Multi-channel Network Interface Controller |
| MUP | Modify User Password |
| MUSAC | Multipoint Switching And Conferencing Unit |
| MUSAC-A | Multipoint Switching And Conferencing Unit Attenuation |
| Mux | Multiplexer |
| MV | Mega Volt |
| MVC | Model View Controller |
| MVDS | Multipoint Video Distribution Service |
| MVTR | Moisture Vapor Transmission Rate |
| MW | Molecular Weight |
| MWBC | Mean Wafers Between Cleans |
| MWT | Monitor Wafer Turner |