1) Alchemical process 
Rubedo is a Latin word meaning `redness` that was adopted by alchemists to define the fourth and final major stage in their magnum opus. Both gold, and the philosopher`s stone were associated with the color red, as rubedo signalled alchemical success, and the end of the great work. Rubedo is also known by the Greek word, Iosis. ==Interpretation......
A temporary redness of the skin. ... Origin: L. Redness, fr. Ruber, red ... (05 Mar 2000) ... 
Type: Term Pronunciation: rū-bē′dō Definitions: 1. A temporary redness of the skin.