A p-group is a special kind of group in math that always has a certain prime number, let's call it "p." A group is like a club or a team, where everyone follows certain rules and does certain things together. But a p-group is like a special club or team that has a certain number of members, let's say "p" members, and they all have a special power that no one else has.
For example, imagine you have a special club for only 3 people and they can fly. And no other club in the world can let their members fly. That's kind of what a p-group is like. It's a group that has a certain number of members with a special power that no other group has.
Now, don't worry if this sounds too complicated. You might not have learned about prime numbers yet in school, but just remember that a p-group is a special kind of group with a certain number of members that all have a special power that no one else has.