What's the Difference Between Stop and Stay?

My son and i were going over his lines in the play when he meets the weird sisters, witches. He says, stay, right? And then conditi out of the line. My son said, why does he say stay? I sad, what do you think he meets en he well, he means stop,. And i saidl what's the difference between stop and stay? What as stay imply that stop might not?And he was thinking dand he said something along the lines of, well, it sounds more like he wants them to spend time with him. They're witches, you know, they av you know, the listen that didn't.