A term typically reserved for Champagne and sparkling wines ...
A term typically reserved for Champagne and Sparkling Wines, non-vintage or simply “NV” on a label indicates a blend of finished wines from different vintages (years of harvest). To make non-vintage Champagne, typically the current year’s harvest (in other words, the current vintage) forms the base of the blend. Finished wines from previous years, called “vins de reserve” are blended in at approximately 10-50% of the total volume in order to achieve the flavor, complexity, body and acidity for the desired house style. A tiny proportion of Champagnes are made from a single vintage.
There are also some very large production still wines that may not claim one particular vintage. This would be at the discretion of the winemaker’s goals for character of the final wine.