What is the middle section of the entablature where relief sculptures may be found?

The middle section of the entablature that often features relief sculptures is called the frieze. The entablature is divided into three main sections: the architrave at the bottom, the frieze in the middle, and the cornice at the top. The frieze traditionally serves as a decorative band where relief sculptures, inscriptions, or painted decorations can be placed. This placement allows for artistic expression and storytelling, often depicting significant cultural or historical themes in architectural design.

In contrast, the architrave is the lowest part of the entablature, which typically serves a more structural role by resting directly on the columns. The cornice, located at the top, primarily serves a decorative purpose and protects the building from weather elements. The tympanum is not part of the entablature; it refers specifically to the space bounded by the horizontal arch of a door or window and the upper lines of the structure. Thus, the frieze is clearly the correct answer as it is specifically the section associated with relief sculptures in the entablature design.