Classic is a term often used in the world of oenology, but it has different meanings. The dictionary gives a good definition to the basic concept which interests us: ' Classic: forming a tradition or linked to one, often in opposition to more recent schools or theories'. Hence for some Italian DOC or DOCG wines there is the 'Classic' category. This is reserved for production from a given sub-region in the Denomination, often the area where it was first produced.
This is the case for Chianti Classico (where the regulations call for a slightly different grape than for 'normal' Chianti), but also Caldaro Classico, a term reserved for wine produced from certain communes in the province of Bolzano which have the longest tradition of making it. The term classic is also used to identify sparkling wines produce by a second fermentation in the bottle. The phrase 'Metodo Classico' (or 'Metodo Tradizionale') is the Italian equivalent of the French 'MÈthode Champenois', which some have reserved exclusively for Champagne.
The word may change but the technique of making the wine sparkle does not: the base wine is made to ferment a second time in the bottle by adding selected yeasts and left for several months before being bottled again (removing the fermentation residues) and put on sale.