Multi-process architecture is a browser design that splits work across separate operating system processes, instead of running everything inside one large program. A typical browser may use one process for the user interface, others for tabs or page rendering, and additional processes for tasks such as graphics or networking. This separation helps contain faults: if one process crashes, the whole browser is less likely to fail.
In cyber security, this design is important because it creates boundaries that attackers must cross. A malicious webpage might exploit a bug in a renderer process, but it still has to escape the sandbox or compromise another process to reach deeper system resources. Defenders rely on this isolation to reduce the impact of memory-corruption bugs and to make exploitation harder. Browser vendors also use the architecture to apply patches more safely, restart individual components, and limit the damage from a compromised tab or plugin-like component.