AWG is the standard grading used on speaker wire. It stands for American Wire Gauge and is a very useful number to understand. A poorly chosen AWG can compromise the sound quality of your speakers.
Without going into the how’s and why’s, the smaller the number the thicker the cable and the more sound information can be sent through the wire. Running with this, it means that 12AWG is thicker than 16AWG.
So what does this mean for you? Well, you need to match the AWG to the sound system. You also need to consider that the longer the run, the more likely you will hear significant power losses and so need to go a bit thicker. You need to look at what style terminals your speakers and receiver has and you need to decide if you are going to use specialty speaker connectors such as banana plugs.
For a standard system in a standard size room with screw down terminals at both the speaker and receiver 16 AWG is considered the standard choice.
For runs longer than 15m we would recommend going up to 14AWG. For runs longer than 30m I would strongly recommend 12AWG.