Door and window openings — what are the vertical sides called? In wall construction, the two vertical sides of a door or window opening that receive the frame are known as:

Introduction / Context:
Clear terminology around openings aids detailing, finishing, and quantity estimation. Each component around a door/window has a specific name used in drawings and specifications.

Given Data / Assumptions:

• Masonry or framed wall with a formed opening.
• Door/window frame fitted to the opening.
• Standard building terminology.

Concept / Approach:

The vertical members of an opening that receive and abut the frame are called jambs. The term reveal refers to the exposed return surface of the wall at right angles to the frame (often the plastered return), whereas “verticals” is not a standard technical term in this context. Correct naming avoids confusion in specifications such as “plaster to reveals” vs. “fix frame to jambs”.

Step-by-Step Solution:

Verification / Alternative check:

Architectural glossaries and standard details consistently label the two vertical sides of an opening as jambs, with head and sill as the horizontal top and bottom.

Why Other Options Are Wrong:

• “Verticals” is generic and non-technical.
• “Reveals” are the perpendicular returns, not the sides themselves.
• “None of these” is wrong because “Jambs” is correct.

Common Pitfalls:

• Confusing frame members (also called jambs) with the wall jambs; context clarifies usage.

Final Answer:

Jambs.