Original: The PC Guide - Plug and Playplug and play Definition Plug and play refers to both the traditional boot-time assignment of device resources and driver identification, as well as to hotplug systems such as USB and Firewire.
Simplified: The PC Guide - Plug and Playplug and play Definition Plug and play is used to refer to both the configuration of devices at boot time, as well as to system that support adding a device later on.