Frigate and destroyer labels still point to design priorities

How can a reader distinguish a modern frigate, destroyer, and cruiser?

Frigates are generally optimized for ASW, destroyers for air defence and radar stability, while today's cruiser role is often performed by large destroyers and other independently deployed escorts.

Frigates are identified primarily through anti-submarine design choices such as large sonars, quiet machinery, and computing focused on underwater contacts. A relatively broad beam compared with length can reflect an emphasis on manoeuvrability, although that distinction has become less reliable. Destroyers generally emphasize large radars, air-defence weapons, and hull stability that keeps those sensors effective. Modern cruisers are often labelled large destroyers instead. In peacetime, both frigates and destroyers conduct independent presence and diplomacy, preserving much of the old cruising role regardless of formal title.