The definition of a door is, according to Merriam-Webster.com, "a usually swinging or sliding barrier by which an entry is closed and opened." Doors are present in the walls of most structures, allowing access within and egress to the outside. There are many interior and exterior door types serving specific purposes. Doors provide security, prohibit sound and air movement, allow light to enter a room, conceal spaces and serve as architectural elements in a home or building.There are Six types of doors 1. Slab Door, 2. French Door, 3. Screen Door, 4. Sliding Patio Door, 5. Pocket Door, 6. Bi-fold and Bypass Doors.entry doors