Okay kiddo, let's talk about something called "ideal" in set theory.
Imagine you have a big collection of all kinds of toys like puzzles, blocks, and balls. Now, you want to pick some of these toys to play with, but you also have some rules you need to follow.
An ideal set in set theory is like that - it is a collection of sets, where each set follows some rules. These rules are kind of like your rules for picking toys to play with.
For example, you might have a rule that you only want to choose puzzles that have less than 10 pieces. In an ideal set, you might have a rule that each set inside it must contain only certain elements, or must satisfy a certain condition.
A cool thing about ideal sets is that they can help us prove things in mathematics. We can use them to show certain properties are true or false for some other sets we are working with.
So, an ideal in set theory is just a special group of sets that all follow certain rules, kind of like how you only choose certain toys to play with according to your own rules.