Ducat is the official currency of Principality of Gallia as well as the Atlantic Federation, and is often abbreviated as DCT.
In-game usage[]
Gameplay-wise, throughout the series, players can earn Ducat by completing missions. Achieving optional objectives such as killing enemy aces, destroying enemy vehicles, completing missions with minimal number of turns often rewards players with extra cash.
Ducat is usually used to research and upgrade weapons, armors and tanks. There are also a number of extra items that can be bought such as Irene Ellet's reports (VC1), newspapers, bonus missions (VC2), and accessories (VC3) as well as repairing the tank if it is destroyed in a mission (VC3).