1 [uncountable] a feeling of great shock, fear or disgustPeople watched in horror as the plane crashed to the ground.With a look of horror, he asked if the doctor thought he had cancer.The thought of being left alone filled her with horror.She recoiled in horror at the sight of an enormous spider.To his horror, he could feel himself starting to cry (= it upset him very much).Her eyes were wide with horror.
2 [singular] a great fear or hatred of somethinghorror of something a horror of deep waterhorror of doing something Most people have a horror of speaking in public.
3 [uncountable] the horror of something the very unpleasant nature of something, especially when it is shocking or frighteningThe full horror of the accident was beginning to become clear.In his dreams he relives the horror of the attack.
4 [countable, usually plural] a very unpleasant or frightening experiencethe horrors of war
5 [uncountable] a type of book, film/movie, etc. that is designed to frighten peopleIn this section you'll find horror and science fiction.a horror film/movie see also horror story6 [countable] (British English, informal) a child who behaves badlyHer son is a little horror.Idioms

ˈhɒrə(r)
ˈhɔːrər