A horro film is a film that has elicit psychlogical occurence which can elevate ones heartbeat when they portray fear and shock. 
Scary! Do you like them? Or have a favorite?
Horror films usually often aim to evoke nightmares , fears and terror beyond the unknown. I love the movie Halloween.
Halloween is a classic! It really felt like it changed the genre. And such a young Jamie Lee Curtis in the starring role!
Supernatural is often a theme as well as the macabre.
Not so much a fan of the macabre/gory. Thrillers and supernatural and psychological are actually more frightening to me. But I haven't *purposely* sought to watch a horror movie in years.
The films of horror can overlap supernatural fiction as well as thriller genres and fantasy.
Steven King is definitely the king (pun intended) of frightening fiction to movies. Have you read any of his books, or seen the movies based on them?