A mill is like a giant machine that helps turn big things into smaller things. Imagine you have a big box of LEGOs, and you want to make a tiny house. The mill would be like your hands, taking the big LEGO pieces and making them into smaller parts to build your house.
Another way to think about a mill is like a big, strong friend who helps you break down your food into tiny bites so you can eat it easily. Just like how you chew your food to make it small enough to swallow, a mill grinds things like grains or seeds into flour that we can use to make bread or cookies.
Sometimes, a mill can be like a magical spinning wheel. When you turn the wheel, it moves the parts inside the mill to crush or grind things into tiny pieces. This is how people used to make flour a long time ago, using windmills or watermills, which are mills that use the wind or water to turn the wheel.
So, a mill is a special helper that makes big things smaller, just like how you make big tasks easier by taking them one step at a time.