[nana77]

"bottoming out"

Spoiler:

When you press a key, it travels downward. Bottoming out happens when you push the key all the way down until it hits the base. This can make typing loud and tiring.

Topping out is the opposite—it's when the key returns to its highest position after you let go.

Most keys need to move about halfway to register a keystroke. This point is called the actuation point. You don't have to press further, but many people do it out of habit.

Some keyboards have special features to help you avoid bottoming out:

O-rings to soften the impact
Heavier springs for more resistance
Tactile bumps to signal when you've hit the actuation point