The live sound world has five standard cable connectors: TRS and XLR (for balanced connections), TS, RCA, and Banana plugs (for unbalanced connections).
TRS
TRS is the abbreviation for "Tip-Ring-Sleeve." This is the accurate term for 1/4" (or 1/8") balanced connectors. A TRS plug can be found at the end of most headphone cords if you want to know what one looks like. It looks like a standard 1/4" plug with an extra "ring" on its shaft. Thus, the three sections of the shaft are called the Tip, Ring, and Sleeve. TRS connectors are used wherever you need to have two conductors plus a ground (shield) in one plug. A common use is to connect balanced equipment.
XLR
XLR is the trademark name for circular 3-pin connectors developed by Cannon (later bought by ITT). XLR has since evolved into a generic industry term, and many manufacturers now make this style of connector, which has positive, negative, and ground connections. In audio, XLR connectors are typically used to transmit balanced mic and line-level signals to mixers or audio to speakers.
TS
TS stands for Tip-Sleeve and refers to a specific type of 1/4" connector set up for two-conductor unbalanced operation. An insulator separates the tip and sleeve. The tip is generally considered the "hot," or the carrier of the signal, while the sleeve is where the ground or shield is connected. TS cables are best known as guitar or line-level instrument cables.
RCA
RCA connectors are the common name for phono connectors, like the ones used to connect most consumer stereo equipment. In the early 1900s, they became so associated with the RCA Corporation that they became known as the RCA connector. Some mixers have tape of CD inputs and outputs with RCA connectors.
Banana Plugs
A Banana Plug is an electrical connector designed to join audio wires, such as speaker wires, to the binding posts on the back of many power amplifiers or to special jacks called banana jacks. A typical configuration of banana plugs is to have two of them molded together and spaced 3/4 of an inch apart, which is also the spacing of the binding post receptacles on the back of power amps.