here is explaination from microsoft:
when you went to cinema,you bring a umbrella,and you want to have the peopel in cinema to keep the umbrella for you,thn you give them the umbrella,they give you a ticket to prove that they keep theumbrella for you.
Ok,the ticket is handle.Handle is meaningless itself,but you can use that.In brief,MS said about handle:"use it,don't ask what it is!"