Around the exterior of the door unit is the frame system. The frame system consists of jambs and mullposts.
A single or double door unit will consist of two side jambs and a head jamb.
A continuous door with sidelite(s) will include two side jambs, a head jamb and mullpost(s). The jambs and mullposts will have a kerf or cutout to receive the weatherstrip. They will also be machined for hinges and strike preps.
A door unit with boxed sidelites will consist of a door unit with two side jambs and a head jamb, plus individual sidelite units with side jambs and separate head jambs. The sidelite unit is mulled (attached) to the door unit.
There are a number of different frame options available: