Vintage is a synonym for "harvest year," the year that the grapes were harvested and made into wine (not the year the wine was actually bottled, which may have taken place years later). In many ways vintage is also a synonym for the weather and its effect on the grapes throughout the grape-growing year, culminating with the harvest. A lot of pomp and circumstance is attributed to a wine's vintage, but the reality is that even most jug wines are vintage wines. The vintage date—which is clearly listed on the bottle of most single-vintage wines—only becomes important when dealing with quality wines, because some annual harvests produce better-quality grapes than others (whereas makers of jug wines are interested more in consistency than in high quality). The 1993 Burgundy harvest, for instance, was particularly good, resulting in some incredible wines. FYI, by U.S. law, a wine may be vintage dated only if 95% of the grapes used to make the wine were harvested in that year.