Which architectural feature of a Roman house is designed to allow rainwater in?

The architectural feature of a Roman house designed to allow rainwater in is the compluvium. The compluvium is an opening in the roof of the atrium that is typically a quadrangular shape, allowing rainwater to flow into the house. This water would collect in the impluvium, which is a sunken basin located directly beneath the compluvium within the atrium. The design of the compluvium serves both practical and aesthetic purposes; it allows natural light into the interior space while facilitating the collection of water, an essential resource for household use.

In the context of Roman domestic architecture, the compluvium also exemplifies the ingenuity of Roman engineering, as it integrates functionality with the design of the space. The impluvium below serves a crucial role in this system as it channels the water collected from the roof into a usable form, contributing to the household's water supply. This clever architectural structure showcases how Romans effectively managed environmental elements in their living spaces.