A Monopole (or ‘monopoly’ in French) is a area of grape vines controlled by a single winery and can be as small as a single designated vineyard (a select number of rows) or the size of an entire AOP. The Napoléonic inheritance laws typically force vineyards to be so finely divided - négociants are needed to bottle tiny quantities of a wine. The question: does a Monopole guarantee a wine of 'higher quality' - is a matter of some debate.
Example of Monopoles: (in Burgundy - France)
Romanée-Conti and La Tâche - (Domaine de la Romanée-Conti).
A monopole wine is a wine produced from the grapes of a single vineyard - and with that vineyard's name appearing on the wine label.

 

Throughout the history of winemaking and viticulture, the differences in quality between one plot of land and another have been observed with the boundaries of these vineyards well demarcated. In Burgundy, the vineyards of the area are classified with the highest quality vineyards receiving the ranking of Grand Cru. The names of these vineyards will often appear on the front wine label of Burgundy wines in bolder, more prominent print than even the name of the producer.
Monopole wines are generally much higher in price than multi-vineyard wines, and typically produced in limited quantities. Naming the vineyard on the label lets buyers know that the wine inside the bottle was made from quailty fruit that possesses certain unique characteristics.
Though some monopole wines are named for properties owned by the wineries themselves, many of the best vineyards are owned by independent growers who don't produce any wine of their own. Instead, they grow grapes on behalf of winery clients, who pay growers on the volume of the harvest.
Grapes from top winegrowers are usually in great demand, which allows them to charge top dollar for their grapes. So are monopole wines better than non-designated wines? Only if you prefer the characteristics of the fruit and resulting wine that comes from those particular vineyard sites - enjoy the journey.