Modern combatant labels still conceal specialized design choices

What meaning remains in the modern distinction between corvettes, frigates, destroyers, and cruisers?

Their sizes overlap, but optimized roles, survivability, self-support, sensor integration, and machinery treatment still create real design differences.

Modern frigates can be understood as anti-submarine cruisers and destroyers as air-warfare cruisers, despite overlapping size and weapons. A corvette is closer to an OPV able to defend itself, while a cruiser can prosecute air, surface, and submarine threats and sustain itself on distant deployments. Shared radar or VLS labels conceal different design priorities: quiet machinery and rafting for ASW, stability and radar height for air defense, plus the computing power, cooling, and integration each mission requires. Combining top-tier performance in every role forces a costly hull full of sensors, processors, pumps, and power systems, often leaving surprisingly little room for missile cells.