Oxidative: Refers to winemaking practices that deliberately expose the wine to oxygen, such as the use of open-top fermentors and racking. Traditional winemaking exposes the wine to some air, but does not result in oxidized notes. An aggressively oxidative approach can result in nutty notes, as seen in wines such as Sherry or vin jaunes from the Jura.
Oxidized: Describes wine that has been exposed too long to air and taken on a brownish color, losing its freshness and perhaps beginning to smell and taste like Sherry or old apples. Oxidized wines are also called maderized or sherrified.
Racking: The practice of moving wine from one container to another for aeration or clarification, leaving sediment behind.
Reductive: Refers to winemaking practices that reduce a wine's exposure to oxygen, such as the use of stainless steel tanks and inert gases to minimize contact with air. This is done to maximize a wine's fresh fruit flavors. However, in some cases it can result in "reduced" aromas, considered a flaw.
Reduced: Commonly used to describe a wine that has not been exposed to air and has developed stinky aromas due to reductive chemical reactions (as opposed to oxidation). Reduced notes in a wine generally result from the presence of volatile sulfur compounds, or mercaptans; these notes include rotten eggs, rubber, struck matches, sewage and even skunk. These off aromas may dissipate after exposure to air through decanting or swirling the wine in the glass.