Question

Which term refers to an object that is critical to the characters in a film, but may be insignificant to the viewing audience?

Answer 1

A MacGuffin is that object in a film which is critical to the characters, but carries insignificant meaning for the audience.

A MacGuffin, a term introduced and widely used by Alfred Hitchcock is some element which drives the plot. The audience is not very concerned with the specifics of it.