a piece of equipment for climbing up and down a wall, the side of a building, etc., consisting of two lengths of wood or metal that are joined together by steps or rungs
Example: to climb up/fall off a ladder
stairs [plural] a set of steps built between two floors inside a building.
Example: 1. We had to carry the piano up three flights of stairs. 2. The children ran up/down the stairs. 3. at the bottom/top of the stairs. 4. He > remembered passing her on the stairs.
Look at this castle playhouse, children can climb up into the first floor of the playhouse via a panel with many small holes that children can put their feet in to climb.
What is it or are they called? a ladder or stairs?