What is meant by a prehung door?
Prehung doors are installed in the frame before they are shipped to the building site or the lumber yard. They have significantly simplified the installation of a door. Prior to the era of prehung doors, a door was shipped without the frame or any hardware. This required a skilled installer to construct a frame, see that it was square and true, install hinges and then carefully fit the door to the frame so that it operated freely.