| Word | Description |
| LAN | A Local Area Network (LAN) is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines. |
| LCD | Liquid Crystal Display. A type of flat screen display. |
| Lens Calculator Software | A computer program for specifying correct lenses. |
| Lens Calculator Wheel | Used for calculating a lens size or distance from a camera to the subject. |
| Line Amplifier (Video line corrector) | A device to make good the loss of signal strength and quality due to long cable runs. |
| Line Fed Camera | A camera that receives its power along the same cable that is used to send its picture back to the monitor. |
| Line Lock | To synchronize the field sync pulses, of an AC powered camera, to the frequency of the voltage input (line voltage). |
| Linux | A freeware, clone version of the UNIX‚ System V release 3.0 kernel that runs on PC x86 machines and other platforms. |
| Local Area Network (LAN) | A local area network (LAN) is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines. |
| Looping | Video input of a piece of video equipment both unterminated and including the relevant sockets for the extra coaxial cables. |
| LS | Level of Sensitivity. This is to set the sensitivity for comparing differences between consecutive images. The greater the differences, the more likely the motion will be detected. |
| Luminance (Y) | The part of a video signal that consists of the monochrome data. |
| Lux | Metric measure of the light striking a surface. The light available from that surface will depend on how reflective it is. |