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

Moreover, its ultra-low infrared emissivity suppresses thermal radiation, hiding objects from heat-seeking cameras. — Mrigakshi Dixit, Interesting Engineering, 21 Sep. 2026

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

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

Infrared emissivity fell in parallel, pointing to materials that could endure the extreme environments of heat and radiation. — Chelsea Haney october 11, New Atlas, 11 Oct. 2025

Word History

First Known Use

1880, in the meaning defined above

Rhymes for emissivity

• absorptivity
• affectivity
• collectivity
• conductivity
• connectivity
• corrosivity
• creativity
• diffusivity
• directivity
• effectivity
• exclusivity
• expressivity

Medical Definition

emissivity

noun

emis·​siv·​i·​ty ˌem-ə-ˈsiv-ət-ē  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