Short definition
A legally defined geographic region where grapes are grown, with rules governing grape varieties, yields, and winemaking methods.
An appellation is a legally protected place name on a wine label. Bordeaux, Chianti, Napa Valley — each is an appellation with its own rules about which grapes can be planted, how many tons per acre, and minimum aging. Smaller appellations are generally more specific and prestigious. A wine labeled "Pauillac" (a village in Bordeaux) tells you more than one labeled just "Bordeaux."