Relay is a decentralized information highway which relays notes and other stuff. These relays can be set up public and private. The end goal is to have true decentralized communication which cannot be censored.

Extreme Example : Alex Jones could effectively run Nostr on his own relay and people can join without the threat of censorship.

And this is just the Notes side of things. There will be much more to come when “the other stuff” is concocted.

I could probably dive further but that’s a Birds Eye view.