stepladder

/ˈstɛpˌlædər/
noun
  1. A portable ladder with flat steps and a hinged frame that can stand on its own, used for reaching high places.
    • The painter set up a stepladder to reach the top of the wall.
    • She used a stepladder to change the light bulb in the ceiling.
    • Always make sure the stepladder is fully open and locked before climbing.