Also known as: 踏み台
A step stool is a short platform for a person to gain a small amount of height. A step stool may appear as a short Stool-like single platform, a short Stepladder, or a short portable set of stairs. Step stools are usually between 1 to 3 steps, and they don't exceed 4 steps.
Step stools are commonly found in places where items may be placed out of reach, such as libraries, stores, and kitchens. They're also frequently used for some vehicles, such as Recreational Vehicles where there might be a slight drop leaving the vehicle.