The term madeira is used to refer to a fortified wine that is made on the Portuguese island of Madeira. It was originally sold to ship captains who would expose it to motion, sunlight, and sea spray on long voyages. This gave it unique characteristics. Today, winemakers recreate the oxidative environment on the island.
Acidity
Acidity in wine is the level of acid that the wine contains. Wines with more acid in them taste more tart or sour.