Movie term, invented by Hitchcock, to refer to any interchangeable object --diamonds, secret plans, computer disk, rare animal etc.-- that is the focus of the action in the plot, but which has no significance to the plot itself. Example: In _The Pink Panther_, the diamond is the McGuffin. It could have been anything.
MCGUFFIN
Meaning of MCGUFFIN in English
Slang English vocab. Английский сленговый словарь. 2012