The term 'swinging barrier' can be described as a GATE, which is a four-letter word. A swinging barrier is a type of GATE that is designed to open and close in a swinging motion. It is commonly used in areas where access needs to be restricted, such as in parking lots or other areas with limited access. The swinging barrier is typically made of metal and is designed to swing open when someone approaches it, allowing them to pass through. It then swings back into place, preventing anyone else from entering.