Interior (French intérieur) has since around 1900 denoted the deliberate design of the inside (as opposed to the outside) of a building, especially a European residential construction (cf. Library, Infirmary, Church architecture, Town hall). The interior is determined by architectural structure (arrangement and height of rooms) and by permanent (ceilings, floors, walls, chimneybreasts) and mobile fittings in reciprocal relation to the usage of the room.