EMISSIVITY

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

2. 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.

3. 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).