Question

The circular opening at the top of a dome is termed as

• A. Oculus
• B. Lantern
• C. Rose window
• D. Clerestory

Hint:

Recall the Latin word for eye: it names the open circular hole left at a dome's crown, as seen at the Pantheon in Rome.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the architectural term used for a circular opening left at the crown (apex) of a dome.

Step 2: Key Concept:
In dome construction, the topmost point can be left open instead of closed, both to cut the weight of the dome near its crown and to let in daylight. This circular opening at the very top of a dome is called an oculus. The best known example is the oculus of the Pantheon in Rome, a single unglazed circular opening about 8.2 m across that is the only source of light for the whole interior.

Step 3: Checking the other options:
A lantern is a small turret-like structure with its own windows, placed on top of a dome or roof to let in light; it sits above the dome as a separate built piece rather than being an opening within it, so option (B) is wrong.
A rose window is a large circular stained-glass window set into the facade of a Gothic church wall, not into a dome, so option (C) is wrong.
A clerestory is a row of windows placed high up in a wall, above eye level, to bring in light and air; it belongs to walls, not domes, so option (D) is wrong.

Step 4: Final Answer:
The circular opening at the top of a dome is called an oculus.
\[ \boxed{\text{Oculus, option (A)}} \]