In paint sheen is a measure of?

In paint, sheen refers to the level of gloss or shine on the surface once the paint has dried. It is measured on a scale from flat or matte (no shine) to high gloss (very shiny), with various levels in between, such as eggshell and satin. The sheen affects not only the appearance but also the durability, washability, and how light reflects off the painted surface. Higher sheen levels tend to be more resistant to stains and easier to clean.