What term refers to public baths in ancient Roman society?

The term that refers to public baths in ancient Roman society is "Thermae." These were large, monumental complexes that included various bathing facilities such as hot baths, warm baths, and cold baths, as well as areas for socializing and exercising. The thermae served not just as places for hygiene but also as social centers where people gathered for leisure, relaxation, and communal activities.

In contrast, "Balneae" refers to smaller, often more private baths that were less grand in scale compared to the thermae. "Spelaeum" refers to a cave or cavern, which is unrelated to bathing structures. "Frigidarium" describes the cold room in a bath complex where bathers would cool off, but it is not a term that encompasses the overall concept of public baths. The broader term "Thermae" encompasses the entirety of the public bathing experience in Roman culture, making it the correct choice.