Which type of finish is characterized by a smooth surface with well-defined fine lines or striations?

A satin finish is characterized by a smooth surface that possesses a subtle sheen, making it distinct from other types of finishes. The well-defined fine lines or striations on a satin finish provide a level of detail and refinement that enhances the surface's appearance without reflecting too much light, unlike glossy finishes. This type of finish strikes a balance between the hard reflections of a gloss finish and the dullness of a matte finish, allowing surfaces to appear elegant while still revealing some textural qualities.

In contrast, a gloss finish is highly reflective and smooth but tends to lack the fine striations that characterize a satin finish. Meanwhile, a matte finish absorbs light and typically does not showcase the defined lines, resulting in a flat appearance without any sheen. Lastly, a textured finish emphasizes irregularities or patterns on the surface, which moves away from the smoothness associated with a satin finish. Therefore, the key traits of a satin finish align perfectly with the provided description, affirming its role as the correct choice.