What term refers to a warship that is equipped with iron plating for protection and was first used during the Civil War?

The correct term that refers to a warship equipped with iron plating for protection, which was first prominently used during the Civil War, is "Ironclad." Ironclads represented a significant advancement in naval technology, marking a shift from traditional wooden ships to those that could withstand heavy fire thanks to their armored hulls. Notably, during the American Civil War, famous battles between ironclad ships, such as the Monitor and the Merrimack, illustrated their effectiveness and signified a transformative moment in naval warfare. This innovation highlighted the growing importance of industrial capabilities in military conflicts.

The other terms, such as frigate, corvette, and galleon, refer to different types of ships. Frigates are fast, maneuverable ships generally armed with guns, corvettes are smaller types of warships typically used for patrol and escort duties, and galleons were large sailing ships used primarily from the 16th to 18th centuries, mainly for trade and warfare in pre-modern naval engagements. None of these encompass the specific technology of iron plating central to the definition of ironclads.