Old World wine refers primarily to wine made in Europe but can also include other regions of the Mediterranean basin with long histories of winemaking such as North Africa and the Near East. The phrase is often used in contrast to "New World wine" which refers primarily to wines from New World wine regions such as the United States, Australia, South America and South Africa. The term "Old World wine" does not refer to a homogeneous style with "Old World wine regions" like Austria, France, Georgia, Italy, Portugal, and Spain each making vastly different styles of wine even within their own borders. Rather, the term is used to describe general differences in viticulture and winemaking philosophies between the Old World regions where tradition and the role of terroir lead versus the New World where science and the role of the winemaker are more often emphasized. In recent times, the globalization of wine and advent of flying winemakers have lessened the distinction between the two terms with winemakers in one region being able to produce wines that can display the traits of the other region—i.e. an "Old World style" wine being produced in a New World wine region like California or Chile and vice versa.

Wine is an alcoholic drink made from fermented fruit. Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made from grapes, and the term "wine" generally refers to grape wine when used without any qualification. Even so, wine can be made from a variety of fruit crops, including plum, cherry, pomegranate, blueberry, currant, and elderberry.