The word "classical" refers to something that is traditional, well-established, or relating to ancient times. It can also describe a type of music or art style that is considered classic or timeless. Full definition
The world of classical music has had a very turbulent week. (npr.org)
However, he is intensely interested in classical music. (furiousdreams.com)
On the other hand, if he's reacting because he's scared of the other dog's presence, you need to work with classical conditioning techniques only. (dogtrainingbasics.com)