What does the term "dry" signify in relation to vermouth?

The term "dry" in relation to vermouth specifically indicates a less sweet style of vermouth. In the context of vermouth, "dry" refers to the absence of the sweetness that characterizes sweeter varieties of vermouth, such as sweet red vermouth. Dry vermouth has a more herbal and less sugary profile, making it a popular choice for cocktails where a lighter, less sweet flavor is desired. This style is often used in classic cocktails like the Martini, where a hint of vermouth complements the primary spirit without overwhelming it with sweetness.

The bitterness referenced in the first option pertains more to the general flavor profile of some vermouths, but it's not the defining characteristic linked to dryness. The third choice regarding alcohol content does not directly correlate to the sweetness level. Finally, clarity or appearance is not a factor in defining whether a vermouth is dry or sweet; both styles can be clear or have different colors. Thus, recognizing "dry" as a specific indicator of lower sweetness is essential for understanding vermouth categories.