- noun a measure of how well a material allows radiation to pass through it, measured as the ratio of incident radiation to transmitted radiation
- The capacity of glass to transmit solar energyin visible light, as well as ultraviolet and infrared ranges. Transmittance is measured in percentages of each type of light.
- For a body or material which is irradiated, the proportion of the incident radiation transmitted. Put another way, transmittance = (1 - absorptance). Also called transmittaney, or transmission (5).