Why Is The Book Holes Called Holes?

I think that the book is called holes firstly because the boys had to dig holes every day at Camp Green Lake, because they were looking for something. Secondly because when Stanley was sent to Camp Green Lake, he thought it was unfair, and that he should have not been sent because he hadn't done anything and the shoes had fallen from the sky, this is a hole because there is missing information, and the authorities didn't research and later sent to Camp Green Lake unfairly. Finally, there were short stories in the book; at the beginning, there seem to be lots of gaps, but as the story develops, each of those short stories connect with Stanley’s story. They were connected, because Stanley's great-great grandfather was on that story and supposedly the curse started there. Another example of this connection is that Madam Zeroni was obviously Zero's kin, because Zero's actual name is Hector Zeroni. And the last reason is that Kate Barlow was once a good woman with a loving heart; but when M. Walker and some other men killed Sam, all her love became anger and hatred, and she had a hole in her heart.