An heiress refers to a woman who is set to inherit a substantial amount of wealth, usually from a family member, such as a parent or relative. In the context of Siobhan Roy from the TV show "Succession," it suggests that Siobhan is expected to inherit a significant fortune or business empire.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Siobhan Roy of "Succession," e.g.. Explanations are generated by AI and may be inaccurate.