What is gossip?

I’m not talking Perez Hilton or Entertainment Tonight, I’m talking about in our personal lives. Is it gossip if you are sharing a story that you know for a fact to be true but it isn’t your story to share? Is it gossip if you mention someone else’s name in any context? Is it gossip when I share a story about my ex with my sister who takes my side and shows support? Is it gossip when I ask a friend about another friend I haven’t seen in awhile? In your opinion what constitutes gossip?