In draft scripts for the film that would become Star Wars ‘A New Hope’, the term “Stardestroyer” refers to two-man fighters flown by what would become the Galactic Empire. The film’s second draft features four Star Destroyers chasing a single Rebel ship, but the tremendous costs incurred by Industrial Light & Magic when production began helped lead Lucas to use a single “terrifyingly large” Star Destroyer instead of four.

ILM built a 259 centimeter (102 inches) Star Destroyer equipped with internal lighting for The Empire Strikes Back (1980). The Empire Strikes Back also introduces the “Super Star Destroyer”, also referred to as a “Star Dreadnought”. The shooting model for the Super Star Destroyer Executor in The Empire Strikes Back (1980) and Return of the Jedi (1983) was 282 centimeters (111 in) long.

The first film ‘A New Hope’ (Episode IV from 1977) featured the Imperial I-class Star Destroyer that would be replaced by slightly different Imperial II-class Star Destroyer in Empire Strikes Back (Episode V from 1980). Several differences existed between the Imperial I and Imperial II-class Star Destroyer, including the replacement of the tractor beam targeting array between the command tower’s sensor globes with a communications tower, as well as the removal of point defense weaponry.

JMAS aka Aaron | Wookieepedia
Imperial II-class Destroyer technical drawing.

The Imperial II was also built with a heavily reinforced hull, stronger deflector shields, and greater firepower than the original Imperial I class. The prominent quad heavy turbolaser and heavy ion cannon turrets flanking the surface of the Imperial I-class Star Destroyer were also replaced with batteries of eight-barreled turbolasers or ions in unarmored barbette mountings. Another new feature included two parallel “claws” for grappling smaller starships placed in the ventral secondary docking bay.

The wedge-shaped Imperial Star Destroyer is a capital ship bristling with weapons emplacements. Turbolasers and tractor beam projectors dot its surface. Its belly hangar bay can launch TIE fighters, boarding craft, land assault units, hyperspace probes, or be used to hold captured craft. In the days of the Empire, its bustling bridge would be staffed by the finest crewers in the Imperial Starfleet. Its presence in a system mark matters of extreme Imperial import. Though, as is typical of the Empire, not even the Star Destroyer was enough to sate the Imperial hunger for displays of power. Larger vessels, such as the Super Star Destroyer, dwarf even these giants.

Starwars.com