Acoustic and classical are both guitars that are made with a light, hollow wooden body. The main difference between these two is that the acoustic generally has steel strings and can sometimes come with a jack so it can be plugged into an amp. Also, different genres are played on it such as country, blues and folk whether as on the classical, there are other genres played such as flamenco, Spanish and baroque. Famous musicians at the moment for the acoustic are Ed Sheeran and Taylor swift. But for the classical, the famous musicians are older, like Isaac Albeniz or Tarrega. Here is an example of someone playing the classical guitar