Noun | 1. | ![]() bi-fold door - an interior door building, edifice - a structure that has a roof and walls and stands more or less permanently in one place; "there was a three-story building on the corner"; "it was an imposing edifice" door - a swinging or sliding barrier that will close the entrance to a room or building or vehicle; "he knocked on the door"; "he slammed the door as he left" accordion door, folding door - an interior door that opens by folding back in sections (rather than by swinging on hinges) |