The crossword solution for the term MELLOW, AS WINE is AGE, which is a three-letter word. Wine mellows with AGE, as the flavor and aroma of the wine develops over time. This is due to the chemical reactions that occur in the aging process, such as oxidation, esterification, and polymerization. As the wine ages, the tannins soften and the acidity decreases, resulting in a smoother, more balanced flavor.