1911 Encyclopædia Britannica/Commodore
COMMODORE (a form of “commander”; in the 17th century the term “commandore” is used), a temporary rank in the British navy for an officer in command of a squadron. There are two kinds, one with and the other without a captain below him in his ship, the first holding the temporary rank, pay, &c., of a rear-admiral, the other that of captain. It is also given as a courtesy title to the senior officer of a squadron of more than three vessels. In the United States navy “commodore” was a courtesy title given to captains who had been in command of a squadron. In 1862 it was made a commissioned rank, but was abolished in 1899. The name is given to the president of a yacht club, as of the Royal Yacht Squadron, and to the senior captain of a fleet of merchant vessels.