What is the name of the technology that saves resources on invisible objects?

Question

3D

In some version of Unity, the following algorithm was introduced: the engine understands which objects the player sees and which not, and draws only what is visible.
I can not find a specific name for such a technology.

Answer 1

Occlusion culling and frustrum culling.
https://docs.unity3d.com/en/530/Manual/OcclusionCu...

Answer 2

Also simpler options:
Renderer.isVisible
MonoBehaviour.OnBecameVisible()