Tension and release
Also said as Build and release, Relief
Letting worry build, then letting it go. A long held threat followed by safety hits harder than either alone, and the relief is often what players remember the most.
Tension needs an end to mean anything. If a horror game is always frightening, players get used to it within minutes and stop being afraid.
Say it
“After the chase, cut the music completely and bring the lights up. Put the save point right there. Don't start the next threat until the player has left that room by choice.”
Where you’ve seen it
The early Resident Evil games have save rooms: safe rooms with a typewriter and calm music. No enemies come in, and hearing that music after a long corridor is a physical relief.
Not to be confused with difficulty
Tension is how much you dread what might happen. A scene can be hugely tense with almost no real danger.