Signal
In plain terms
A software interrupt notifying a process of an event.
Going deeper
Signals are asynchronous notifications the OS sends to processes to request actions like termination or to report events. They let the OS poke a process.
Under the hood
Common signals: SIGTERM (graceful stop), SIGKILL (force), SIGINT (Ctrl+C); handlers customize responses.
Examples
SIGKILL, SIGTERM, Ctrl+C, process control, kill command, handlers.
Think of it like...
Like tapping someone on the shoulder with a specific message to act on.