A door feature is an element of a door that serves a specific purpose. The term DOOR FEATURE can refer to a JAMB, which is the vertical side of a door frame, a peephole, which is a small hole in a door that allows someone to see who is outside without opening the door, a keyhole, which is a hole in a door that allows a key to be inserted and turned to open or LOCK the door, a KNOCKER, which is a metal piece attached to a door that can be used to make a loud noise to alert someone inside the house, a LOCK, which is a device that secures a door and prevents it from being opened without a key, a KNOB, which is a round handle used to open and close a door, and a SILL, which is the bottom part of a door frame.