The phrase "little stool" refers to a small chair or seat that is typically low to the ground. It can also be used metaphorically to describe a position of low importance or influence in a situation. Full definition
They're the perfect little stool for chats in the kitchen or a place for a quick snack. (theinspiredroom.net)
My desk as well as the drawers underneath it and the cute little stool where I've hidden stuff I don't know what to do with inside. (sincerelyshannon.com)
It really is the perfect little stool height for teeth brushing and hand washing. (mamasdance.com)