emissivity
noun
emis·siv·i·ty
ˌe-mə-ˈsi-və-tē 
ˌē-ˌmi-ˈsi-
plural emissivities
: the relative power of a surface to emit heat by radiation : the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature
Examples of emissivity in a Sentence
Recent Examples on the Web
However, as the radiator surface is exposed to ionizing radiation, its emissivity decreases, and after 5 years in space the required area increases by about 40 percent.
—
IEEE Spectrum,
11 June 2026
The cooling side reflects over 90% of incoming sunlight while achieving a mid-infrared emissivity of 97.1%.
—
New Atlas,
25 May 2026
There’s a system on a computer chip that controls the process, which works in conjunction with low-emissivity glass coatings that allow for electrical pulses.
—
Andrew P. Collins,
The Drive,
8 Jan. 2026
In contrast, black paint will deteriorate under prolonged sun exposure, becoming gray and decreasing its emissivity.
—
Brendan Rascius,
Miami Herald,
22 Aug. 2025
The closer the sample emissivity, the more similar the colour in the infrared image.
—
Prabhat Ranjan Mishra,
Interesting Engineering,
6 Aug. 2025
Concrete, for example, is rated at 0.85, brick can range between 0.73 and 0.93 depending on its composition, and bare metals like brass can have emissivity values as low as 0.03.
—
Joan Meiners,
USA TODAY,
10 Sep. 2024
Both reflectivity and emissivity depend on the wavelength of light.
—
Rhett Allain,
WIRED,
25 Aug. 2023
At the base Premium level, the roof has a special coating called low-e, or low emissivity, to keep the interior cool by blocking some wavelengths of light.
—
Kristin Shaw,
Popular Science,
13 Mar. 2023
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IEEE Spectrum,
11 June 2026
The cooling side reflects over 90% of incoming sunlight while achieving a mid-infrared emissivity of 97.1%.
—
New Atlas,
25 May 2026
There’s a system on a computer chip that controls the process, which works in conjunction with low-emissivity glass coatings that allow for electrical pulses.
—
Andrew P. Collins,
The Drive,
8 Jan. 2026
In contrast, black paint will deteriorate under prolonged sun exposure, becoming gray and decreasing its emissivity.
—
Brendan Rascius,
Miami Herald,
22 Aug. 2025
The closer the sample emissivity, the more similar the colour in the infrared image.
—
Prabhat Ranjan Mishra,
Interesting Engineering,
6 Aug. 2025
Concrete, for example, is rated at 0.85, brick can range between 0.73 and 0.93 depending on its composition, and bare metals like brass can have emissivity values as low as 0.03.
—
Joan Meiners,
USA TODAY,
10 Sep. 2024
Both reflectivity and emissivity depend on the wavelength of light.
—
Rhett Allain,
WIRED,
25 Aug. 2023
At the base Premium level, the roof has a special coating called low-e, or low emissivity, to keep the interior cool by blocking some wavelengths of light.
—
Kristin Shaw,
Popular Science,
13 Mar. 2023
Cite this Entry
“Emissivity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/emissivity. Accessed 28 Jun. 2026.
Copy CitationMedical Definition
emissivity
noun
emis·siv·i·ty
ˌem-ə-ˈsiv-ət-ē
ˌē-ˌmis-ˈiv-
ˌē-ˌmis-ˈiv-
plural emissivities
: the relative power of a surface to emit heat by radiation : the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature
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