The term “deep” refers to a location that is:

The term "deep" in anatomical terminology is used to describe structures that are further away from the surface of the body. It indicates a position that is located internally or toward the core, as opposed to superficial, which refers to structures close to or on the body surface.

For example, the heart is considered deep to the ribcage because it is located within the thoracic cavity, protected by the ribs. Understanding this terminology is crucial for accurately describing the location of different body parts in relation to one another.

In this context, the other terms are defined differently: "closer to the body surface" refers to superficial structures, while "higher in elevation" and "lower in elevation" relate to changes in vertical position, which do not pertain directly to the concept of deep versus superficial anatomical relationships.