Well, a "free party" is when a group of people get together and have a big dance party without paying any money to enter. It's kind of like having a party with your friends, but with lots and lots of people you may not know.
Usually, free parties happen in outdoor spaces like fields or warehouses, and people bring their own music and sound systems. It's like a big music festival, but without all the fancy stages and ticket prices.
Sometimes, people who host free parties can get in trouble with the police because they aren't allowed to have big events without certain permits. But sometimes, people will host them secretly so nobody finds out.
Overall, free parties can be a lot of fun and a great way to dance and socialize with other people who love music. But it's important to also remember to be safe and careful since they can sometimes be in uncontrolled environments.