Side-lights
Glass panels on one or both sides of the main entry door.

Transom
Box, arch or oval-shaped panel above the door made entirely or partially of glass.

Door insulation
Material used to increase the thermal resistance and airtightness of the building envelope and conduits thereby reducing heat loss in a house.

Side jamb (hinge side)
Vertical element positioned on the same side as the handle that ensures the airtightness on the side between the wall and door opening.

Side Jamb (handle side)
Vertical element positioned on the same side as the hinge ensures airtightness on the side between the wall and door opening.

Jamb Header
Upper element positioned above the door that ensures the airtightness between the wall and door opening.

Opening
Exterior doors open either to the inside (inswing) or to the outside (outswing).

Right hand or left-hand doors
Single exterior doors typically swing inward. The door will open on the side where the hinges are located: if the hinges are on the right, the door is right-handed and will open on the right; if the hinges are on the left side, the door is left-handed and will open on the left.

Threshold
Horizontal bottom part of a wood door frame. The threshold slopes slightly to the exterior to facilitate drainage.

Entry System
Fully integrated unit including the door, frame, threshold and weatherstripping. The door, already on its hinges and in the frame, is easier to install than it would have been starting from separate elements.

Pre-drilled holes for the lock
Holes for the lock are generally drilled, which is why it is important to choose the handle and lock when you order the door.

Glazing
Generic term for the transparent or sometimes translucent material installed in doors, not necessarily designating glass.

Exterior doors are subject to the National Building Code which stipulates that doors opening to the outside may not measure less than 32”W and 75”H. Municipalities may increase the required width and height stipulated in the Code, but never decrease. Consulting a building inspector before you start work could save you time and problems. There is no R-value (thermal resistance value) requirement for exterior doors; however, before you purchase a door, check the insulation capacity and, when and where it is needed, ensure there is sufficient weatherstripping.
Though doors between the house and garage are not considered to be exterior doors, they should be insulated and equipped with a self-closing device to prevent carbon monoxide and other vehicle exhaust gasses from entering the house.
Function, energy-efficiency, security, appearance and compatibility are the considerations that should guide your choice of an exterior door. There is a wide range to choose from; at the end of the day, you need to choose a door that will harmonize with your decor, reflect your taste, and meet all your expectations and requirements.