(Abbreviation for Input Output Port) Input Output Port - part of the PC that is used for passing data in and out of a computing device. This is normally located on the back of the PC. The port can be a Serial Port - data is sent/received one bit at a time through a cable containing a single wire, or a Parallel port where the data is sent/received through a cable containing several pieces of wire so that more than one bit at a time can be processed.