The definition of reflection is to bounce or throw back. In our usage reflection is the bouncing of electromagnetic energy from a surface. The term reflectance is defined as the ratio of the amount of electromagnetic radiation, usually light, reflected from a surface to the amount originally striking the surface - Websters New World Dictionary this definition implies that some of the energy striking a surface is not reflected. And we have learned through basic high school physics that electromagnetic energy is either, reflected, transmitted, or absorbed by the surface it strikes. Surface particles are small relative to the wavelength.
Light is reflected in a single direction.
The angle on reflection is equal to the angle of incidence. Sometimes called 'mirror' reflection Radar instruments have a hard time identifying water bodies because the wavelength is much longer than the general character of the surface roughness. Specular reflectance helps and hinders remote sensing depending where the sensor is situated relative to the outgoing radiation. Also called isotropic or lambertian reflectance. Many natural surfaces act as a diffuse reflector to some extent.