Final answer:
A wave is a disturbance that carries energy from one place to another. Mechanical waves require a medium to travel through, while light does not.
Step-by-step explanation:
A wave is a disturbance that travels or propagates from one place to another. Waves transfer energy from one place to another, but they do not necessarily transfer any mass. Mechanical waves, such as sound waves and water waves, require a medium, such as a solid, liquid, or gas, to travel through. On the other hand, light is not a mechanical wave and can travel through a vacuum.