[ em-uh-siv-i-tee, ee-muh- ]
/ ˌɛm əˈsɪv ɪ ti, ˈi mə- /

noun Thermodynamics.

the ability of a surface to emit radiant energy compared to that of a black body at the same temperature and with the same area.

Origin of emissivity

First recorded in 1875–80; emissive + -ity
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for emissivity

British Dictionary definitions for emissivity

/ (ɪmɪˈsɪvɪtɪ, ˌɛm-) /


a measure of the ability of a surface to radiate energy; the ratio of the radiant flux emitted per unit area to that emitted by a black body at the same temperatureSymbol: ε
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012