Emissivity

·add. ·noun Tendency to emission; comparative facility of emission, or rate at which emission takes place;.

II. Emissivity ·noun Tendency to emission; comparative facility of emission, or rate at which emission takes place, as of heat from the surface of a heated body.

III. Emissivity ·add. ·noun 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).