Wine Glossary
Definition: Vintage
[VIHN-tihj] Term that describes both the year of the actual grape harvest and the wine made from those grapes. In the United States, the label may list the vintage year if 95 percent of the wine comes from grapes harvested that year. If a blend of grapes from 2 years or more is used, the wine is called non-vintage or NV. Some champagne and sparkling wine producers are using the term multi-vintage to describe wines made from a blend of 2 or more years. The multi-vintage designation is to reflect the fact that the vintners are purposefully blending cuvees from different years to achieve a superior house style. Although it's often assumed that a vintage wine is one of superior quality, that's not necessarily true. Some vintages are simply considered better overall than others. That's because the quality of the harvest varies from one year to another. In addition, an individual wine may be better or worse than others of a particular vintage because of the originating vineyard's mesoclimate or because of the winemaking process it underwent. An excellent year for a growing region translates to a generally superior quality, which means there are more choices for fine wines of that vintage. So consumers should view a vintage year only as a general guideline. In the end, each wine must be judged on its own merit.
Source: Answers.com; Wine Lover's Companion - R & S Herbst