(engineering) The quality of a surface, in terms of its roughness, microscopic pattern (lay) and macroscopic pattern (waviness).

plural of surface finish

Mail which is transported by motor vehicle, by railway, or by seacraft, but not by aircraft.

plural of Fermi surface

plural of faying surface

Either of a pair of surfaces that are in contact in a joint.

plural of Morin surface

(topology) A halfway model of the sphere eversion, featuring fourfold rotational symmetry.

(physics) The layer of molecules at the surface of a liquid that is responsible for surface tension / (ecology) The layer of surface water that forms a boundary between sea and air

In a steam boiler, the aggregate surface exposed to fire or to the heated products of combustion, especially of all the plates or sheets that are exposed to water on their opposite surfaces.