This was true in the past, but in many modern navies the destroyer is the _only_ class. Some fleets with a single class call their ships frigates instead, even

This was true in the past, but in many modern navies the destroyer is the _only_ class. Some fleets with a single class call their ships frigates instead, even if they're about the same size as comparable destroyers. In navies that do use destroyers and frigates, destroyers are larger than frigates.