What is an horror movie?

I am not a big fan of movies, but in my city theaters these movies are
running currently so please open the site below and help:

http://www.megaplextheatres.com/showtimes/south_jordan_district.php

P.S. I was also wondering does it show anywhere on there site next to
the movie or something like which category is this etc. Example:
Horror, etc. (because this is the reason I am asking for your guys
help) Thanks.