Answer: APSE

An apse is a semicircular or polygonal recess in a building, typically found at the eastern end of a church or mosque. It often contains an altar or a niche, such as a mihrab in Islamic architecture, which indicates the direction of Mecca for prayer. In this case, the word "apse" refers specifically to the architectural feature where the mihrab is located in a mosque.

Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Where the chair of St. Peter sits in St. Peter's Basilica. Explanations are generated by AI and may be inaccurate.