Reflectance values express the percentage of light that is reflected back from a surface, the difference having been absorbed or transmitted by the surface.
Definition of AXIAL. 1. : of, relating to, or having the characteristics of an axis.
Definition of axis for English Language Learners. : 1  the imaginary straight line that something (such as the Earth) turns around. : 2  a straight line that divides a shape evenly into two parts.