What is the generation of an opposite (sound) wave to absorb (mute) the target wave called?

Question

Audio

I remembered a picture that shows that a sound wave can be completely extinguished if a reverse wave is applied to it. I assume it's used for echo cancellation.
What is the name of this physical phenomenon?

Answer 1

Reverse anti-phase

Answer 2

Principle of noise canceling headphones.
Be sure to adjust the gain.