There are many genres, sub-genres, and themes that take place in movies. I’m going to keep it simple for the language of the blog, but if you are interested in the science and construction of Horror, I recommend The Dark Descent by David G. Hartwell. It contains an edited historical overview of horror fiction.
IS THIS HORROR?
Horrors purposes is to invoke fear and dread.
Horror can have an element of the fantastic.
Horror usually involves an evil force, event, or personage breaking into the everyday.
WHAT ABOUT THRILLER?
Thriller is a broad genres that is meant to invoke suspense.
Thrillers main tool the cover up. (Keeping information from the audience)
Thrillers characters are usually in conflict with each other or an outside force.
The main point here. is the feeling the medium is trying to invoke. the lines can get very blurry and we haven’t even gotten into theme or sub genres but basically, the Bourne Identity is a thriller, but not horror.