Meaning of emissivity

em•is•siv•i•ty

Pronunciation: (em"u-siv'i-tē, ē'mu-), [key]
— n. Thermodynamics.
  1. 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.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.