A corvette is a small warship. It is traditionally the smallest class of vessel considered to be a proper (or "rated") warship. The warship class above the corvette is that of the frigate, while the class below was historically that of the sloop-of-war.
The modern types of ship below a corvette are coastal patrol craft and fast attack craft. In modern terms, a corvette is typically between 500 tons and 2,000 tons although recent designs may approach 3,000 tons, which might instead be considered a small frigate.
The word "corvette" is first found in Middle French, a diminutive of the Dutch word corf, meaning a small ship, from the Latin corbis, meaning "basket".
The rank "corvette captain", equivalent in many navies to "lieutenant commander", derives from the name of this type of ship. The rank is the most junior of three "captain" ranks in several European (e.g., France, Spain, Italy) and South American (e.g., Argentina, Chile) navies, because a corvette, as the smallest class of rated warship, was traditionally the smallest class of vessel entitled to a commander of a "captain" rank.
During the Age of Sail, corvettes were one of many types of warships smaller than a frigate and with a single deck of guns. They were very closely related to sloops-of-war. The role of the corvette consisted mostly of coastal patrol, fighting minor wars, supporting large fleets, or participating in show-the-flag missions. The English Navy began using small ships in the 1650s, but described them as sloops rather than corvettes. The first reference to a corvette was with the French Navy in the 1670s, which may be where the term originated. The French Navy's corvettes grew over the decades and by the 1780s they were ships of 20 guns or so, approximately equivalent to the British Navy's post ships. The British Navy did not adopt the term until the 1830s, long after the Napoleonic Wars, to describe a small sixth-rate vessel somewhat larger than a sloop.
Most corvettes and sloops of the 17th century were around 40 to 60 ft (12 to 18 m) in length and measured 40 to 70 tons burthen. They carried four to eight smaller guns on a single deck. Over time, vessels of increasing size and capability were called corvettes; by 1800, they reached lengths of over 100 ft (30 m) and measured from 400 to 600 tons burthen.