What term describes a wine that is extra dry?

The term that describes a wine that is extra dry is "Brut." In the context of sparkling wines, particularly Champagne, "Brut" refers to a style with very little residual sugar, resulting in a crisp and dry taste. This designation indicates that the wine has a sugar content of less than 12 grams per liter, appealing to those who prefer a more pronounced acidity and less sweetness in their wines.

The other terms refer to different levels of sweetness in wine. "Sec," which translates to "dry" in French, typically designates a dry wine but does not necessarily imply an extra-dry level like Brut. "Demi-sec" means "half-dry" and indicates a noticeable sweetness, making it less dry than Brut. "Doux," on the other hand, means "sweet" in French, designating wines that have a higher residual sugar content, which stands in contrast to the concept of extra dryness embodied in Brut. Thus, "Brut" is the most accurate term for describing an extra dry wine.