What is the name of the pool that collects rainwater in a Roman house?

The correct answer is "Impluvium." In a Roman house, the impluvium is specifically designed to collect rainwater that flows in from the roof through an opening called the compluvium. The impluvium is a shallow basin located in the atrium, where the water would be stored for various household uses, such as drinking or bathing.

The atrium itself is the main room of a Roman house that may include the impluvium but is not a water collection feature in itself. The compluvium refers to the opening in the roof that allows rainwater to enter the impluvium, but it is not the pool that collects the rainwater. The peristylium is a columned courtyard that usually surrounds the atrium and serves a different function in the layout of a Roman home.