Footstool

Okay, imagine you are sitting on a chair and your feet can't touch the ground, so you feel uncomfortable. A footstool is like a little step for your feet to rest on so that they are not just hanging in the air. It's like when you are trying to reach something up high and you need to stand on a stool, but this time instead of standing, you can rest your feet on it to feel more comfortable. It's basically a small piece of furniture that helps you relax while sitting down.