Cables are generally two or more pieces of wire used to transmit signal from one device to another. Cables are generally classified by gauge when referring just to the wire, or to the connectors at either end of the cable, also sometimes known as "heads" or "ends."
There are several common types of connectors used in audio and video, and this is by no means a comprehensive list. The most commonly used are:
1/8" or 3.5mm - Another type of TRS cable, these are most commonly known for their use in consumer headphones and earbuds. There are also some instruments which output to this size connector. Generally found in more budget audio applications.
XLR - XLR cables are three pin connector most often associated with microphones, which is why cables of this type are often called "Mic cables." This connector is low impedence, and is also used in direct boxes and outboard gear.
Speakon - Speakon cables are mostly commonly used for larger live rigs, and are designed to connect speakers to more powerful amplifiers both safely and securely.
RCA - RCA cables are the small red, white, and yellow cables often found on television sets. In audio, they are most often used for auxiliary stereo inputs on mixers or other similar devices.
*Please update this section if you are familiar with common cables used in video production.