What does the term 'specular reflection' refer to?

The term 'specular reflection' specifically refers to the reflection of light off smooth surfaces, such as a calm body of water or a mirror. In this context, light rays striking a smooth surface reflect at definite angles, allowing for a clear and sharp image to be produced. The key characteristic of specular reflection is that it maintains the coherence and directionality of the reflected light, which leads to distinct visual effects. This is in contrast to other types of reflection, where surfaces may be rough or uneven, resulting in diffuse reflection, where light scatters in many directions. Specular reflection is fundamental in understanding how mirrors and shiny surfaces function in optical systems.