Which term describes the vertical member around a doorway on the interior side?

• A. Jamb
• B. Casing
• C. Architrave
• D. Sill

Answer: (A)

The term that describes the vertical member around a doorway on the interior side is "Jamb." In architectural terminology, the jamb refers specifically to the vertical components or the posts that frame the sides of a door opening. They are crucial for providing structural support to the door and help with the proper installation of the door itself.

Casing surrounds the door and provides a finished look, but it is not specifically the vertical member; it includes the trim that covers the gap between the wall and the jamb. Architrave is similar but typically refers to the entire framework around a door or window, and it may encompass both the jambs and the casing. A sill is the horizontal member that forms the bottom edge of a door frame or window, often associated with windows more than doors. This clarifies why "Jamb" is the correct term for the vertical members around a doorway.