How to disable terminal for non root users, I need to know if I can, for security reasons.
Change shell to
For more information about difference between nologin and false check man pages.
I advice not to do that, not recommended. Terminal in Linux distributive is very important thing and disabling or removing it may cause troubleshoots. Usually by default you are asked to enter password during installation of Ubuntu and it's for root purposes of course so common user won't be able to do stuff with sudo as he doesn't know root password and doesn't have root privileges.
Other way out is to create an account for this person @ System > Administration > Users & Groups> Set the user type to "desktop account". This is not going to keep it away from opening a terminal, but the user will not be able to install or remove software packages, cannot run any command from terminal that requires the use of "sudo", and cannot make changes to the system properties from the command line or GUI.
And yet one more way I happened to found is to find any terminals that you have installed on your system (gnome-terminal, xterm, etc)
xterm is in /usr/bin/xterm
Now add any users you want to access the terminal to the terminal group.
So I guess these are ultimate solutions and will help you.