Star Dreadnought, sometimes spelled Star Dreadnaught, was a formal designation for some of the largest and strongest battleships in the starfleets of regional and multiversal governments. The term "Super Star Destroyer" was also applied colloquially to some of these ships by the Allies and Axis. In these cases, Star Dreadnoughts were noted as being the largest Super Star Destroyers. In turn, the lower-case term star dreadnought could be used to describe Super Star Destroyers in general. Various classes of Star Dreadnoughts were known to have served in the Kuat Drive Yards defense fleets, the Axis Navy, the Allied Navy Fleet and the Coalition Fleet. Their sizes eclipsed most conventional warships, peaking with the Executor-class at 19 km in length, and the Eclipse-class, with its unequaled mass and weaponry.