The Ferengi rank equivalent to captain, held by the commander of a starship, who runs the vessel as a business venture on behalf of its crew of investors.
DaiMon is the title of the officer in command of a Ferengi vessel. A DaiMon is expected to lead his crew to profit as well as to victory, and a commander who wastes money can be removed by his own officers.
The rank is introduced with the Ferengi themselves in The Next Generation episode The Last Outpost, in which DaiMon Tarr confronts the Enterprise-D at Delphi Ardu. DaiMon Bok pursues a private and unprofitable revenge against Picard in The Battle and is relieved of command for it. DaiMon Tog abducts Lwaxana Troi in Menage a Troi, and DaiMon Bractor stumbles into a Starfleet war game in Peak Performance.
The title is heard less often in Deep Space Nine, whose Ferengi are mostly civilians, although Ferengi warships and their DaiMons are still referred to.