Usually three small wires with prongs coming from the center of a circle the size of a pen cap. The Yellow cord is Video, the Red is Right Audio, and the White is Left Audio. However, if you match the colors properly, you could use any of the colors for either video or audio. RCA stands for "Radio Corporation of America" and they somehow attached their initials to this type of jack.

For cameras with a single Mini out there are RCA cables that have a Mini plug on one end. If the plug has only two lines on it (and thus only two RCA style plugs on the other end) it can still be used to transmit either one video and audio channel or two audio channels as needed.