A rotunda is a circular or cylindrical building, often with a domed roof. It is typically used as a public space or as a part of a larger building, such as a courthouse or university. In the context of the clue you provided, the rotunda refers to the central building at the University of Virginia, designed in the Jeffersonian architectural style.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Jeffersonian design at the heart of the University of Virginia. Explanations are generated by AI and may be inaccurate.