The in-flight entertainment device is a computer, usually mounted on the seatback of the chair in front of the passenger, that offers in-flight entertainment options such as movies, music, games, an in-flight map, and more. Abbreviated as IED, hopefully, for travelers, it doesn’t translate to Intermittent Explosive Disorder or, worse, an Improvised Explosive Device 😉
In-flight entertainment devices are usually available on longer flights to avoid passenger restlessness. For passengers without a seatback in front of them, it may be mounted on a bulkhead (wall) or elsewhere.
See also: In-Flight Entertainment.