A theoretical "perfect black" object, or one which allows absolutely no light to be reflected from its surface. Even the blackest blacks on Earth—such as lampblack, black velvet, soot, etc.—reflect as much as 3% of the light that hits it. Blackbodies have historically contributed to science and physics—it was physicist Max Planck's study of blackbody radiation that led to his nascent version of quantum theory in 1900. Blackbodies are also used in the determination of color temperature. See Color Temperature.
Another perfect blackbody is the so-called "black hole" of astrophysics, a collapsed star of such high density and gravitation that no light can escape it.