An Apple 8-pin or 30-pin plug and cradle into which an iPhone, iPad or iPod touch is inserted to play music on externally powered speakers and/or to charge the unit. The dock is built into self-amplified music boxes, or it is connected via a USB cable to a computer, USB charger or home theater equipment. See Apple dock connector and Lightning connector.
Apple's Universal Dock
The dock provides a base station for connecting an iPod or iPhone to a computer or music system. Apple's tiny iPod Shuffle does not use a dock connector. (Image courtesy of Apple Inc.)
Directly into the Receiver
This iPod/iPhone dock plugs directly into the back of Onkyo A/V receivers via a proprietary plug and socket. The cradle (top) shows Apple's 30-pin plug, which was superseded by the 8-pin interface. See Apple dock connector
and Lightning connector