What does "surface layer" mean?

The layer of molecules at the surface of a liquid that is responsible for surface tension

What is a synonym for "surface layer"?

Common synonyms include: boundary layer, coating, cover a surface, cursory, exterior, film.

noun

noun ·Rare ·Advanced level

Noun

1
The layer of molecules at the surface of a liquid that is responsible for surface tension
2
The layer of surface water that forms a boundary between sea and air