ماكغافن

Also known as McGuffin, maguffin, plot coupon

In fiction, a MacGuffin (sometimes McGuffin) is an object, device, or event that is necessary to the plot and the motivation of the characters, but insignificant, unimportant, or irrelevant in itself. Thus, the use of a MacGuffin in a narrative is a plot device. The term was originated by Angus MacPhail for film, adopted by Alfred Hitchcock, and later extended to a similar device in other fiction.