How is the term “surface area” used in geometry?
Measurements and Transformations
Read more from

Logically, the surface area is the area of a given surface. There are several ways to interpret this in geometry: Area can mean the extent of the surface region on a twodimensional plane. Surface area (often called the lateral surface area, although there is a difference) formulas for threedimensional objects are more complex—all the surface areas are added around the outside of the object, from a cube to a sphere.
Surface area is commonly denoted as S for a surface in three dimensions, and A for the surface area of a twodimensional plane (commonly, it is simply called “the area”). But be careful: The surface area of a threedimensional object should not be confused with “volume”—or the total amount of space an object occupies. (For more about volume, see below.)