Why is the ninth month called September?
1753, in cosmetic sense, "blush," from French rouge "red coloring matter," noun use of adjective "red" (12c.), from Latin rubeus, related to ruber "red" (see red). Replaced native paint in this sense. The verb is attested from 1777. Related: Rouged; rouging. The same word had been borrowed from French in Middle English with the sense "red color; red" (early 15c.).