Okay kiddo, so pruno is a type of wine that people used to make a long time ago in a place called Cilento. But they didn't make it like regular wine that you buy at the store. They made it in a very special way, in prison!
You see, the people who were locked up in prison weren't allowed to have things like grapes or other ingredients to make wine. But they found a way to make pruno using things they could get their hands on, like fruit cocktail, bread, and sugar. They mixed it all up in a container with water, let it sit for a few days, and then it turned into pruno!
Now, you might be wondering why they called it pruno. Well, the word "pruno" actually comes from the Spanish word "purgar," which means "to purify." That's because the people who made pruno wanted to "purify" themselves and forget about their troubles while they were in prison.
But you should know that making pruno in prison is not allowed, and it's also not safe to drink if you're not careful. It's important to always listen to grown-ups and not try to make pruno on your own. Stick to drinking regular grape juice for now, okay?