The different elements of the wine's taste - fruit, acidity, tannins, alcohol - are in harmony with no one aspect predominating.
This is a difficult term. When tasting coffees for defects, professional tasters use the term to describe a coffee that does not localize at any one point on the palate; in other words, it is not imbalanced in the direction of some one (often undesirable) taste characteristic. As a term of general evaluation, balance appears to mean that no one quality overwhelms all others, but there is enough complexity in the coffee to arouse interest. It is a term that on occasion damns with faint praise. The Mexican sample should be most balanced, but it has less to balance than the other two coffees. If you tasted the Yemen Mocha against a standard Ethiopian Harrar you would probably sense how the Yemen coffee is similar to the Harrar, but much more balanced. A well-balanced coffee contains all the basic characteristics to the right extent.