- Mollier diagram
- momentum correlation
- momentum transfer
- monatomic molecule
- monitor
- monochromatic emissivity
- monochromator
- monocord switchboard
- monoenergetic
- monopole
- monostable circuit
- Moseley number
- motor meter
- mounting plate
- moving constraint
- mu metal
- motional induction
- motor stage
- motorize valve
- mould growth
- mould inhibitor
- moulded glass
- mountain effect
- movable contact
- moving grate
- muffling system
- muliphoton ionization
- multicircuit evaporator
- multicomponent mixture
- multielement array
- multipass evaporator
- multipath transmission
- multiple
- multiple reflection
- multipole radiation
- multitube cooler
- moistureproof seal
- molecular acoustics
- molecular beam
- molecular physics
- molecular size
- Mossotti field
- motor effect
- motor generator
- mounting
- mounting position
- moving element
- multiblade damper
- multichamber design
- multichannel analyser
- multicircuit condenser
- multideck counter
- multifrequency code
- multilevel freezer
- multiline subset
- multipass condenser
- multiplate freezing
- multiple converter
- multiple expansion
- multiple moment
- multiplet structure
- multiplication
- multiplying medium
- multipolarity
- multistage evaporation
- multistage rocket
- multitier counter
- multiturn
- mush winding
- mutual action
- mutual coupling
- multipath
- multiphase behaviour
- multiphoton absorption
- multiple earthing
- multiple glazing
- multiple modulation
- multiplet
- multipolar machine
- multisection unit
- multistable
- multistage expansion
- multistage throttling
- multistream cooler
- multitubular boiler
- mushroom
- muting switch
- mutual admittance
- mutual attraction
- mutual impedance
- myopia
- N-electron
- naked
- nanoparticle
- naphtalen
- Napierian base
- native gold
- multichannel evaporator
- multichannel selector
- multicoil evaporator