I think it is 'epidermis'.
The crust
earth's crust, soil layer, outer layer
its another word for outer.
Big dipper is an outer space word. Black hole is another outer space word that begins with the letter b.
The curved outer surface of a circle is the perimeter.
The outer surface of the bone is called the periosteum.
Tectonic plates
Tectonic plates
Tectonic plates.
tyre service
The crust or the surface.
Pinna is also known as the outer 'Ear'