Definitions for "Emissivity"
the rate of emission of heat from a bounding surface per degree of temperature difference between the surface and surrounding substances (called by Fourier external conductivity).
The property of emitting radiation; possessed by all materials to a varying extent.
Ratio of radiation emitted by a surface to the radiation emitted by a black body at the same temperature under similar conditions. May be expressed as total emissivity (for all wavelengths), spectral emissivity (as a function of wavelength), or goniometric emissivity (as a function of angle).
Keywords:  emittance, see
see emittance
Tendency to emission; comparative facility of emission, or rate at which emission takes place;