Star Destroyers and White Stars show labels can mislead

Which familiar science-fiction ships behave like cruisers even when their official names say otherwise?

Star Wars' Imperator-class and Babylon 5's White Stars and Hyperions repeatedly perform cruiser work such as presence, scouting, escort, and patrol.

The Imperator-class Star Destroyer spends much of its time on presence, pursuit, and independent cruising despite its name, with the fleet battle in Return of the Jedi as a notable exception. Babylon 5's White Stars conduct reconnaissance, probing attacks, screening, and tripwire duties rather than stand as durable battle-line ships. Their small crews and dependence on friendly support also limit how long they can maintain an independent presence. Hyperion-class cruisers patrol, escort capital ships, lead small groups, and arrive early when the Earth Alliance wants to make a point. These examples show that repeated mission patterns provide a stronger classification tool than fictional nomenclature alone.