I found this on Google. You could have done the same and gotten your answer much faster than two hours.
"Waves that transfer energy through a medium are called mechanical waves. Waves that can transfer energy through a vacuum and do not need a medium are electromagnetic waves. Electromagnetic waves are produced by the vibrating charged particles, resulting in changes in electric and magnetic elds.Apr 21, 2020"
What do we call waves that must travel through a medium?
2 answers
thanks bob