Answer:
Disturbance
Step-by-step explanation:
A wave is a disturbance that travels through a medium and transfer energy from one point to another without causing any permanent displacement of the medium itself. Example of waves are water waves, sound waves, electromagnetic radiations etc. Some waves are mechanical in nature i..e they require material medium before they can travel (before propagating) while some are electromagnetic which requires no material medium before they can propagate (they propagate naturally) example are the radiowaves, infrared rays, visible light etc.