Vintage (from the online Oxford Dictionary)
1 the year or place in which wine was produced.
2 a wine of high quality made from the crop of a single identified district in a good year.
3 the harvesting of grapes for winemaking.
4 the grapes or wine of a particular season.
5 the time that something was produced.
1 referring to vintage wine.
2 referring to something from the past of high quality.
Vintage fashion acquired its name from vintage wine, a better way of categorizing second-hand clothing that belonged to a certain era. Since second-hand could mean any item, it didn't do the older and more original pieces any justice.
There is no exact rule/definition of what is vintage, there are different schools of thought but there is a general idea of it. As with vintage wine, it has to pertain to a year it was produced, be available in limited supply and to some people its a collectible item especially if it was from a luxury label. It doesn't necessarily mean it has to be from a luxury designer, but just the fact that its a piece that pertains to an eras fashion like shoulder padded 80's jackets or flapper dresses.
There is some debate that a vintage item can only be 15 years or older and c