That's slightly different than the controlling terminal. The controlling terminal (in UNIX) is the terminal the job is associated with for signals, but not necessarily the terminal the job is connected to. For example, running a command pipeline or redirected command from the shell will make the process not have a terminal connected to it, but it will still have a controlling terminal. A cron job will have neither a connected terminal or a controlling terminal. The difference is subtle but can be important for things like daemons.