Abbreviation for Tip Ring Sleeve. This is the descriptively accurate term used to describe 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. They look like a standard 1/4″ plug with an extra section in them. The three sections of the shaft are called the Tip, Ring, and Sleeve (a “standard” 1/4″ connector just has a tip and sleeve). TRS connectors are used wherever it is desired to have two conductors plus a ground (shield) in one plug. Common uses are as a way to connect balanced equipment (where the TRS plug has a positive, negative, and ground connection), or stereo unbalanced equipment (left and right are on the Tip and Ring, with a common ground) like headphones, or as an insert for your mixer or other processor (Tip or Ring is the send with the other being used as the return and again ground is common).