The repeating disturbance in a medium is called a wave.

Here's a breakdown:

* Medium: A substance that carries the disturbance. This could be a solid, liquid, or gas.

* Disturbance: A temporary change in the medium, like a vibration or compression.

* Repeating: The disturbance occurs repeatedly, creating a pattern of movement.

There are two main types of waves:

* Mechanical waves: These require a medium to travel, like sound waves traveling through air or water waves traveling through water.

* Electromagnetic waves: These do not require a medium and can travel through a vacuum, like light waves.

Let me know if you'd like to know more about any specific type of wave!