The exterior part of anything that has length and breadth; one of the limits that bound a solid, esp. the upper face; superficies; the outside; as, the surface of the earth; the surface of a diamond; the surface of the body.

A magnitude that has length and breadth without thickness; superficies; as, a plane surface; a spherical surface.

The horizontal plane whose elevation above sea level equals the field elevation. At stations where the field elevation has not been established, the surface refers to the ground elevation at the observation site.

That which has length and breadth only.

a superficial aspect as opposed to the real nature of something; "it was not what it appeared to be on the surface"

a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight

involving a surface only; "her beauty is only skin-deep"; "superficial bruising"; "a surface wound"