The difference between slander and gossip is a legal difference. Gossip is idle chit chat; often negative and hurtful about other people. I always think of the movie Mean Girls. Gossip is often used as a way to earn social collateral among peers and one of the main currencies of high school – less so between boys. Knowledge is power and power is currency. Gossip can be used as a psychological slight of hand to distract the crowd from looking at the person spreading the gossip. In the most extreme cases the people who are the target of vicious gossip attempt suicide. Gossip can be true or false; but what matters is that the information is being spread that was probably shared in the strictest of confidence.
Slander is grown up gossip with legal consequences. Slander is the legal term for making a false statement about someone that hurts their reputation and can be grounds for a civil law suit for damages. The key to slander lies in the false statement resulting in a damaged reputation; be it against a business, a person, a group, or a country.
Libel is the legal term for knowingly making a false statement about a person, country, business, etc in images or print. It makes me wonder how the National Inquirer and the Weekly World News get away with printing false stories. These tabloid publications don’t get sued as often as they could be because they plead ignorance – their defence is that claim to not the know the story is false and it is very difficult to prove what someone does or does not know. Furthermore, the celebrities who are often the target of the stories in these tabloids don’t want to bring more attention to themselves by being embroiled in a lawsuit. It makes more PR sense for them to ignore the allegations.
So; in summary: gossip is idle chit chat which can be harmful, but isn’t always. Slander is knowingly making false statements about a person or organization that harms their reputation. Libel is knowingly making a false statement about a person or organization through print or pictures.