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 arch for Students. 1  1 : a usually curved part of a structure that is over an opening and serves as a support (as for the wall above the opening) 2  2 : something that has a curved shape like an arch the arch of the foot.