A binding post is a connector that usually allows a wire to screw into it, or stay attached by some other means. It is often found on the back of stereo speakers. A terminal is somewhat the same as a binding post. A phono jack is a type of jack that is many times used in devices as the point where an adapter cord connects to the device. Its schematic symbol is often placed on the device, as well as the input voltage and polarity. A phono jack is the kind you plug your headphones in. A plug is a male connector that goes into the receptacle, a female connector.