you have ever had to fill out the many forms for screenwriting
contests, you will find that they all have their own definition of
the standard is definitely to make the screenwriting synopsis
short. A paragraph or two would suffice, if you're
lucky. Most forms only give you a few lines to make your
brief statement about your screenplay.
means, you will have to choose what you think is the
"biggest" idea in your story--the main premise of why
you wrote it in the first place.
example, in the movie, Seabiscuit, writer, producer,
director, Gary Ross, says that one of the big ideas of this movie
is about what happens when the American Dream is
taken away from you.
an exercise, try writing a paragraph or two about a recent movie
you watched and see if you can write a synopsis about the main
ideas in the movie. Then try doing the same with your own
script, before or after the actual writing.