ELI5: Explain Like I'm 5

Smart contract

A smart contract is like an agreement between two people but it's written in a computer language instead of on a piece of paper. Just like an agreement, it says what both people have to do. The computer then checks that both people have done what they said they would do and then it automatically makes sure that each of them gets what they were supposed to get. It's like having a robot that double checks that the agreement is followed.