What is a cornice in architectural terms?

A cornice in architectural terms refers to the crowning molding typically located directly under the pediment. This architectural feature serves both a functional purpose, such as directing rainwater away from the building's walls, and an aesthetic one, as it adds visual interest and detail to the design of a structure. Cornices are often elaborately designed and can vary in style depending on the architectural period and the overall design of the building. They help to define the silhouette of the structure and can enhance its grandeur and elegance.

Regarding the other options, while a decorative element on the facade might be an important part of architecture, it does not specifically define a cornice. Support beams are crucial for structural integrity but do not fit the definition of a cornice. Lastly, decorative flooring relates to the ground level aspects of design, which is entirely separate from the meaning of a cornice. Understanding the distinct attributes of these architectural features clarifies why the choice of a crowning molding under the pediment aptly describes a cornice.