SIGTSTP
Ctrl+Z: the pause that comes from the keyboard and can be refused.
The terminal stop: SIGSTOP's polite sibling, rung by the terminal driver when you press Ctrl+Z. It was born with BSD job control, in the late seventies — the then-radical idea of pausing a program and keeping the same terminal.
Unlike its sibling, this one can be caught: editors like vim use the chance to restore the screen before stopping — and to take it back on fg. The shell keeps the list in jobs; bg releases the process into the background.
$ vim notas.md
^Z
[1]+ Stopped vim notas.md
$ jobs
[1]+ Stopped vim notas.md
$ fg
(vim comes back with the screen intact)