surface
n. countable B1 Intermediate Oxford US //ˈsɝfəs// UK //sˈɜːfɪs// sur·face
n. the top or outside layer of something. It is the part you can see or touch, like the top of a table or the outside of a ball.
n. the outermost boundary of an object or a body; the exterior layer of a solid or liquid. In a mathematical context, it refers to a two-dimensional locus of points in three-dimensional space.
The surface of the table is smooth and cold.
The divers returned to the surface of the water after exploring the coral reef for an hour.
Geologists study the Earth's surface to understand how tectonic shifts and erosion have shaped the landscape over millions of years.
From Middle French surface. By surface analysis, sur- + face. Doublet of superficies.
Usage
Often used with the preposition 'on' or 'below'.