1. the fraction or percentage of light or other electromagnetic radiation that passes through a material
Usage: physics; optics

Examples

• The transmittance of the glass window was measured at 90 percent.
• Scientists tested the transmittance of various plastic films.
• High transmittance is important for optical lenses.
• The material’s transmittance decreased as its thickness increased.
• UV transmittance through the atmosphere varies with altitude.
• The filter’s transmittance was highest in the green wavelength range.