Terrois or Terreni (territory) refer to specific areas. Is a concept that has several things included like the grape varieties, elevation and shape of the vineyard, the nature of the soil, climate and seasonal conditions as well as the local yeast cultures.
Wine is usually made from one or more Varietal of Vitis Vinifera, such as Pinot Noir, Chardonnay or Merlot
When the predominant grape is one of these varieties in a mixture defined by law as a minimum of 75% or 85%, the result is a Varietal. This is different from a blended wine.
Blended wines are not considered inferior; in fact, some of the world’s most valued and expensive wines that come from regions like Bordeaux and Tuscany are blended from different grape varieties of the same Vintage.
The classification and sale of wine is governed all over the world. European wines tend to be classified by region (e.g. Bordeaux and Chianti), while others are often classified by grape (e.g. Merlot, Chardonnay). However, regional recognition is leading to increased prominence for some wine labels.
Some blended wine’s names also double as marketing terms, and these names are governed by trademark or copyright laws rather than by specific wine laws.