a pirate or person who scours the seas, especially the Mediterranean, with a vessel armed for war, without commission from any prince or power, in order to plunder merchant vessels. The word is formed from the Italian corsare or corso, or a cursibus, by reason of their courses or excursions. The name was commonly given to the piratical cruisers of Barbary, who took their rise under Barbarossa, about the beginning of the sixteenth century.

A corsair is distinguished from a privateer by this, that the latter acts under a commission, and only attacks vessels belonging to those who are at war with the state whence his commission is derived. Hence the punishment of a corsair is, to be hanged without remission, whereas the crews of privateers are to be treated as prisoners of war. All corsair vessels are good prizes.