transmittance
noun
trans·mit·tance
tran(t)s-ˈmi-tᵊn(t)s 
tranz-
1
2
: the fraction of radiant energy that having entered a layer of absorbing matter reaches its farther boundary
Examples of transmittance in a Sentence
Recent Examples on the Web
Senate Bill 46, passed in 2024, allows vehicle owners to tint their windshields if the tinting allows at least 70% light transmittance.
—
Marina Johnson, Louisville Courier Journal, 18 Sep. 2025
Windshield tinting Under Senate Bill 46, vehicle owners are allowed to tint their windshields if the tinting allows 70% light transmittance.
—Hannah Pinski, The Courier-Journal, 12 July 2024
As the thickness gets closer to a centimeter, light transmittance drops: Berglund’s group reported that 3.7-millimeter-thick wood—roughly two pennies thick—transmitted only 40 percent of light.
—Jude Coleman, Smithsonian Magazine, 19 Dec. 2023
Made of several layers of materials and fabric, they are designed to provide thermal resistance (known as R-value) and prevent thermal transmittance conductivity (known as U-value).
—Heidi Wachter, Treehugger, 14 July 2023
The prototype four-pixel device can switch its light transmittance with less than 5 volts in just 625 microseconds—which would translate to more than 1,000 frames per second.
—IEEE Spectrum, 10 Mar. 2023
Thus, in sunlit nesting environments, less pigmentation will increase the detrimental effect of transmittance, but more pigmentation will increase the detrimental effect of absorbance.
—Seriously Science, Discover Magazine, 1 June 2018
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Marina Johnson, Louisville Courier Journal, 18 Sep. 2025
Windshield tinting Under Senate Bill 46, vehicle owners are allowed to tint their windshields if the tinting allows 70% light transmittance.
—Hannah Pinski, The Courier-Journal, 12 July 2024
As the thickness gets closer to a centimeter, light transmittance drops: Berglund’s group reported that 3.7-millimeter-thick wood—roughly two pennies thick—transmitted only 40 percent of light.
—Jude Coleman, Smithsonian Magazine, 19 Dec. 2023
Made of several layers of materials and fabric, they are designed to provide thermal resistance (known as R-value) and prevent thermal transmittance conductivity (known as U-value).
—Heidi Wachter, Treehugger, 14 July 2023
The prototype four-pixel device can switch its light transmittance with less than 5 volts in just 625 microseconds—which would translate to more than 1,000 frames per second.
—IEEE Spectrum, 10 Mar. 2023
Thus, in sunlit nesting environments, less pigmentation will increase the detrimental effect of transmittance, but more pigmentation will increase the detrimental effect of absorbance.
—Seriously Science, Discover Magazine, 1 June 2018
Cite this Entry
“Transmittance.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/transmittance. Accessed 4 Nov. 2025.
Copy CitationMedical Definition
transmittance
noun
trans·mit·tance
-ˈmit-ᵊn(t)s
1
2
: the fraction of radiant energy that having entered a layer of absorbing matter reaches its farther boundary
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