Transmittance refers to the ability of a material to allow the passage of light or electromagnetic waves through it. Synonyms for transmittance include translucence, transparency, and clarity. Translucence refers to a material that allows light to pass through, but with some degree of scattering or diffusion. Transparency, on the other hand, refers to a material that allows light to pass through without any scattering or diffusion. Clarity refers to the quality of being clear, transparent, and bright. Other synonyms for transmittance include permeability, transmission, and passage. These words all describe the ability of a material to allow something to pass through it without obstruction.