Naval historians often name periods after the largest ship types associated with them. The Dreadnought era takes its name from the ship that starts the period. The ironclad era follows the same convention, while the Age of Sail describes a time when sailing ships were the norm. Each phrase gives naval history a compact period label. Like the other era names in the answer, these labels describe broad patterns rather than exact calendar boundaries.
Notable Point · 1:04-1:32
Dreadnought, ironclad, and sail as naval era labels
Naval history often turns a prominent ship type or means of propulsion into a period name, as with Dreadnoughts, ironclads, and the Age of Sail.