A beautiful shell on the smooth surface of the seaA beautiful shell on the smooth surface of the sea
An astronaut on the surface of the moon with a us flagAn astronaut on the surface of the moon with a US flag
Reflection in the water surface of trees and mountainsReflection in the water surface of trees and mountains
Autumn trees on the background of the river surfaceAutumn trees on the background of the river surface
В математике: граница, отделяющая геометрическое тело от внешнего пространства. Наружная сторона чего-н..