A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several operational roles from search-and-destroy to ocean escort to sea denial.
The term "cruiser", which has been in use for several hundred years, has changed its meaning over time. During the Age of Sail, the term cruising referred to certain kinds of missions—independent scouting, commerce protection, or raiding—usually fulfilled by frigates or sloops-of-war, which functioned as the cruising warships of a fleet.
In the middle of the 19th century, cruiser came to be a classification of the ships intended for cruising distant waters, for commerce raiding, and for scouting for the battle fleet.