A nozzle is the shaped exit at the end of a propulsion system that turns high-pressure, expanding gas into a directed stream. By narrowing and shaping the flow path, it converts thermal and pressure energy into velocity, which produces thrust. In rockets, nozzle geometry strongly affects efficiency, stability, and how much force the engine can deliver.
In cybersecurity, “nozzle” is a useful engineering analogy for a controlled exit path: the single place where traffic, logs, or data are allowed to leave a system. Defenders care about that choke point because it is where rate limits, filtering, and monitoring can be applied. Attackers also look for ways to bypass or widen the exit path, since that can make exfiltration faster or less visible. The core lesson is the same in both fields: the shape of the outlet controls the behavior of the flow.