Macro 
Magneto-optical recording (MOR) 
Mail 
Mail merge 
Mapping drives/ printers 
Margins 
Maximise 
Mb or Mbyte 
MCA 
MCI 
Media 
Media Player 
Meg 
Megabyte 
Megahertz 
Memory 
Memory expansion 
Menu 
Menu bar 
Menu short cuts 
Message box 
Meter/power supply 
MHz 
Microphone 
Microsoft 
Microsoft Exchange 
Microsoft Fax 
Microsoft Network (MSN) 
Microsoft Windows 
MIDI 
MIDI file 
MIDI Mapper 
Minimise 
Mnemonic keyboard shortcut 
Modal 
Modem 
Monitor 
Monochrome monitor 
Monospaced font 
Morphing 
Motherboard 
Motorola 
Mouse 
Mouse-driven 
Mouse driver 
Mouse pointer 
Movie file 
Movie Player 
MPC 
MS-DOS 
MTBF 
Multi-frequency/ -scan/ -sync monitor 
Multimedia 
Multimedia-ready 
Multi-part stationery 
Multi-session compatible 
Multi-tasking 
Music chip 
My Computer