The Latin word "culmen" means peak, the highest point. In music the culmination of the episode is called, which reached the highest voltage, i.e. the most emotionally affecting moment, which leads logic of the entire play.
Cliffhangers can be several for great compositions. Then one of them is the main (sometimes called Central or General), and the other "local".
The culmination is in any melodies. This is usually one of the top sound, accentuated by greater duration and beats of the bar.