Well kiddo, a long time ago, there were groups of people who lived in a place called Poland. Each group had their own way of doing things, like how they talked, what they believed in, and how they lived their daily lives. These groups were called tribes, kinda like how your friends at school are in different groups.
One tribe was called the Polanie, which means "people of the fields". They were the biggest and most powerful tribe in Poland. Another tribe was called the Mazovians, and they lived in the forests. Then there were the Silesians, who lived in the south, and the Pomeranians who lived along the coast of the Baltic Sea.
Each tribe had their own leaders and people who looked up to them. They didn't always get along with each other and sometimes they even fought. But then something happened that brought them all together – they started to form bigger groups and work together to protect their land from invaders. And that's how these tribes eventually became the country we know as Poland today!
So, in simple terms, Polish tribes were different groups of people who lived in Poland a long time ago and had their own way of life. Eventually, they came together to form a united country.