- Membranes
- Memory bandwidth
- Memory effect
- Meniscus
- Menthol
- Mercury
- Mercury cadmium telluride
- Mercury chloride
- Mercury glass
- Mercury oxide
- Mercury poisoning
- Mercury selenide
- Mercury telluride
- Mercury-vapor lamps
- Mesentery
- Mesh
- Mesitylene
- Mesoporous materials
- Mesoporous silica
- Metabolic acidosis
- Metabolic syndrome
- Metabolism
- Metabolites
- Metakaolin
- Metal casting
- Metal detectors
- Metal dusting
- Metal fabrication
- Metal foam
- Metal fume fever
- Metal ions in aqueous solution
- Metal matrix composites
- Metal spinning
- Metallic bonding
- Metallocene
- Metallography
- Metalloids
- Metallothionein
- Metallurgy
- Metalorganic vapour-phase epitaxy
- Metalworking
- Metamorphic rock
- Metamorphism
- Metasomatism
- Metastability
- Metastasis
- Meteorites
- Methane
- Methane emissions
- Methanogenesis
- Methanol
- Methemoglobinemia
- Method of exhaustion
- Methyl acetate
- Methyl groups
- Methyl methacrylate
- Methyl orange
- Methylaluminoxane
- Methylation
- Methylmercury
- Metre per second
- Metric system
- Metrology
- Mica
- Micro pitting
- Microalloyed steel
- Microarchitecture
- Microbial corrosion
- Microcirculation
- Microcline
- Microcontrollers
- Microcytic anemia
- Microelectronics
- Microfabrication
- Microfiber
- Microfluidics
- Micrograms
- Microlenses
- Micromagnetics
- Micrometers
- Micrometres
- Microorganisms
- Microplastics
- Microprocessor
- Microscopic scale
- Microscopy
- Microsecond
- Microsoft Windows
- Microstructure
- Microtome
- Microvoid coalescence
- Microwave engineering
- Microwave ovens
- Microwaves
- Middens
- Migmatite
- Mild hybrid
- Military engineering
- Mill
- Mill scale
- Milling
- Milling cutter
- Millisecond
- Mine reclamation
- Miner
- Mineral acids
- Mineral alteration
- Mineral oil
- Mineral processing
- Mineral spring
- Mineral wool
- Mineralogy
- Mineraloids
- Minerals
- Minimal surfaces
- Minimum total potential energy principle
- Mining
- Minor actinides
- Minute ventilation
- Mischmetal
- Miscibility
- Missiles
- Mixed tensor
- Mixing ratio
- Mobile broadband
- Mobile devices
- Mobile phone
- Model building code
- Model rockets
- Modified atmosphere
- Modified starch
- Modular arithmetic
- Modularity
- Mohr's circle
- Mohr-Coulomb theory
- Mohs scale
- Moiety
- Moisture
- Moisture sorption isotherm
- Molar absorption coefficient
- Molar concentration
- Molar conductivity
- Molar heat capacity
- Molar mass
- Molar mass distribution
- Molar volume
- Mold
- Molding
- Molding sand
- Mole