Victim Is Innocent. A terrorist attacks any person or place. His victim is not his true target. He picks victims as symbols, or for convenience. He picks them to get maximum publicity and to cause maximum alarm.
Target Is Audience.
A terrorist targets an audience. His weapon is not plastic explosive or nerve gas, it is terror. His target is not optic fibers or commuters, it is public will. He claims credit for his crime, or makes sure we learn who did it and why. He wants to force policy his way.