| Word | Description |
| M-PEG | Moving Picture Expert Group. A suite of digital compression tools specifically designed to video images. |
| Macro | Feature allowing you to pre-programme frequent system configurations for selection by a single keystroke or optionally by alarm inputs. |
| Matrix Switcher | A switcher able to route any of its camera inputs to any of its monitor outputs; a name usually reserved for large systems, that often includes telemetry control. |
| Mb | Megabyte, or one million bytes or characters of information. |
| Mechanical Focus (Back-focus,racking) | The mechanical aligning of the imaging device with the focal point of the lens; most important on zoom lenses to ensure the image stays in focus throughout the zoom range. |
| Microwave | Radio frequencies between 1 - 30 GHz used for video transmission over medium/long distance. |
| Modem | Modulator/Demodulator.A device used to convert serial digital data from a transmitting terminal to an analogue signal (carrier) for transmission over a telephone channel or to reconvert the transmitted analogue signal to serial digital data for acceptance by a receiving terminal. |