What is a primary characteristic of wines labeled as "dry"?

Wines labeled as "dry" are defined primarily by the absence of perceptible sweetness, which typically indicates that they have little to no residual sugar remaining after fermentation. This means that the sugars present in the grapes have been completely fermented into alcohol, leaving behind a wine that does not taste sweet.

Residual sugar levels can vary significantly among different styles of wine. In dry wines, the fermentation process converts most, if not all, of the natural grape sugars into alcohol, resulting in a clean, crisp taste profile. Notably, while some dry wines can exhibit flavors that might give an impression of sweetness (due to factors like fruit concentration or oak aging), the key characteristic remains the low levels of residual sugar.

In contrast, the other options describe characteristics not typically aligned with the definition of a dry wine. Sweet, syrupy wines are considered dessert or sweet wines and contain significant amounts of residual sugar. Low acidity and high alcohol content can occur in various wine styles, including both dry and sweet wines, making those attributes insufficient for defining a wine as "dry."