a commissioned naval officer who ranks above a captain and below a rear admiral; the lowest grade of admiral
"The commodore oversaw the squadron, holding the rank just below that of a rear admiral."
A naval officer holding a rank between captain and rear admiral.
"The commodore inspected the fleet, standing in his unique rank above the captains but below the rear admirals."
In plain English: A commodore is an officer who ranks just below a captain and usually commands several ships at once.
"The commodore gave a speech to all the sailing club members at the annual meeting."
Usage: In modern navies, the title of commodore often denotes a senior flag officer commanding a flotilla rather than a specific permanent rank in some countries. Avoid using it to refer to any ship's captain unless specifically addressing that individual by their official designation within a fleet context.
A surname.
"Many people mistakenly believe that Commodore is a naval rank, but it is actually just a common surname in Scotland and Northern England."
The word commodore entered English via the Dutch kommandeur, which itself came from the Middle French commandeur. Originally meaning a commander or someone in charge of an order, it was adopted into English to denote a high-ranking naval officer.