Ok kiddo, let me explain what a valide sultan is in a way that even a 5-year-old can understand.
A valide sultan was a very important person in the Ottoman Empire, which was a huge empire that existed a long time ago, in a far off place called Turkey.
So imagine that the Ottoman Empire was like a big castle, with a very powerful king, who was called the Sultan. The Sultan was in charge of everything, but he also had a special lady in his life who was called the valide sultan.
The valide sultan was usually the mother of the Sultan, or sometimes she could be his wife. She was very important because she had a lot of influence over the Sultan, and she helped him make important decisions that affected the whole empire.
But being a valide sultan wasn't just about being the mother or wife of the Sultan. She had to be very smart, and she had to know a lot about politics and diplomacy. She also had to be very good at managing money and resources, because she was in charge of a lot of the wealth and property of the empire.
In fact, the valide sultan was so important that she even had her own palace, where she lived with her children and her staff. And whenever the Sultan couldn't make a decision, he would often ask his mother or wife for advice.
So that's what a valide sultan was, a very important lady who had a lot of power and influence in the Ottoman Empire, and who helped the Sultan make big decisions that affected the whole kingdom.