Final answer:
The surface that spans horizontally across the top of columns or the top of a wall is called an entablature. It consists of three parts: cornice, frieze, and architrave, and it supports the roof while providing decorative elements.
Step-by-step explanation:
The term referring to a surface that spans horizontally across the top of columns or the top of the wall is entablature. An entablature in the Classical orders of architecture comprises three main parts: the cornice, which is the uppermost section; the frieze, which is a wide central section that may be decorated with reliefs or paintings; and the architrave, the lowest part directly above the columns.
It plays a critical role in classical and neoclassical architecture, supporting the roof and often elaborately decorated to enhance the aesthetic appeal of the building.
The entablature refers to a surface that spans horizontally across the top of columns or across the top of the wall in Classical orders of architecture.
It typically consists of a cornice, a frieze, and an architrave. The entablature plays an important role in supporting the roof and adding decorative elements to the overall structure.