absorptance
This term is a specialized technical descriptor used primarily in physics, optics, and materials science. It refers to a dimensionless ratio, typically expressed as a value between 0 and 1, representing the proportion of energy absorbed relative to the total incident radiation. It is distinct from absorbance, which is a logarithmic measure used in chemistry and spectroscopy to describe the attenuation of light passing through a medium.
Because it describes a specific physical property or a measured ratio, the word is treated as an uncountable noun. It does not refer to a discrete object that can be counted, but rather to a characteristic of a material's interaction with electromagnetic waves.
Meanings
Examples
The coating significantly increases the absorptance of the material in the ultraviolet range.