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

This question checks if you know the correct term for a specific dome feature: the round hole builders sometimes leave open at the very top of a dome.

1. Oculus: this is the Latin word for eye. Architects use it for a circular opening at the crown of a dome that stays open to the sky, letting light and rain fall straight into the space below. The Pantheon in Rome is the textbook case.
2. Lantern: a lantern is a raised structure with its own small windows, sitting on top of a dome, as seen on St Paul's Cathedral or the US Capitol. It is a separate built element, not just a hole in the dome, so it does not match "opening at the top of a dome".
3. Rose window: a rose window is a round, richly patterned stained-glass window set into a wall or facade of a church. It has nothing to do with domes.
4. Clerestory: a clerestory is a strip of windows set high in a wall to bring daylight deep into a tall room. It belongs to walls, not domes.

Only the first term, oculus, describes a bare circular opening at the apex of a dome itself, so option (A) is the answer.

Let's summarize:

• Oculus is the open circular hole at a dome's crown.
• Lantern is a windowed structure built on top of a dome.
• Rose window and clerestory belong to walls and facades, not domes.

So the circular opening at the top of a dome is the oculus, option (A).