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 temperature
Symbol: ε
emissivity in American English
(ˌimɪˈsɪvəti; ˌ ɛmɪˈsɪvəti)
noun
the relative ability of a surface to radiate energy as compared with that of an ideally black surface under the same conditions