Composite Video is a video colour format where the video information is combined into a single channel. It is a composite of three source signals called Y, U and V (together referred to as YUV) with sync pulses. Y represents the brightness or luminance of the picture and includes synchronising pulses, so that by itself it could be displayed as a monochrome picture. U and V represent hue and saturation or chrominance; between them they carry the colour information.
In typical home applications, the composite video signal is usually connected using an RCA Plug (usually represented by a yellow coloured plug, and often accompanied with red and white for right and left audio channels respectively).A BNC connector and higher quality coaxial cables are often used in more professional applications.