Vintage technically refers to a harvest. In wine when a vintage year appears on a label, it means that all the grapes used to make the wine in the bottle came from that year and the same concept is being applied to the likes of Tequila with certain single field producers. A Vintage Cognac means that the Cognac is a single blend from one particular year.
Vintage is also being adopted by gin producers who are foraging for a large portion of their botanicals and where the seasonality mean the flavour will be different year on year despite the recipe not changing. It is also being utilised for hybrid gins that fuse the world of wine and juniper together (either by using grapes to infuse into the spirit such as a Shiraz Gin, or by cutting the distillate using wine instead of water to reduce it to bottling strength).